[extension/skywalkingencoding] add contrib distributions in skywalking_encoding extension (#41916)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description
add contrib distributions in skywalking_encoding extension :
open-telemetry/opentelemetry-collector-releases#1076 (comment)

follow up :
open-telemetry/opentelemetry-collector-releases#1076

Signed-off-by: Jared Tan <jian.tan@daocloud.io>

Author: JaredTan95

extension/encoding/skywalkingencodingextension/README.md

@@ -4,11 +4,12 @@
 | Status        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
 | ------------- |---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
 | Stability     | [alpha]                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
-| Distributions | []                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
+| Distributions | [contrib] |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
 | Issues        | [![Open issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aopen%20label%3Aextension%2Fskywalkingencodingextension%20&label=open&color=orange&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aopen+is%3Aissue+label%3Aextension%2Fskywalkingencodingextension) [![Closed issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aclosed%20label%3Aextension%2Fskywalkingencodingextension%20&label=closed&color=blue&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aclosed+is%3Aissue+label%3Aextension%2Fskywalkingencodingextension) |
 | [Code Owners](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/CONTRIBUTING.md#becoming-a-code-owner)    | [@JaredTan95](https://www.github.com/JaredTan95)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
 
 [alpha]: https://github.com/open-telemetry/opentelemetry-collector/blob/main/docs/component-stability.md#alpha
+[contrib]: https://github.com/open-telemetry/opentelemetry-collector-releases/tree/main/distributions/otelcol-contrib
 <!-- end autogenerated section -->
 
 The `Skywalking` encoding extension is used to unmarshal Apache Skywalking segment traces. Marshalling is not supported.

extension/encoding/skywalkingencodingextension/metadata.yaml

@@ -5,7 +5,7 @@ status:
   class: extension
   stability:
     alpha: [extension]
-  distributions: []
+  distributions: [contrib]
   codeowners:
     active: [JaredTan95]
 

reports/distributions/contrib.yaml

@@ -98,6 +98,7 @@ components:
         - pprof
         - redis_storage
         - sigv4auth
+        - skywalking_encoding
         - text_encoding
         - zipkin_encoding
     processor: