Update changelogs for 0.3.0 (#388)

Signed-off-by: xiaolong.ran <[email protected]>

### Motivation

Update changelog for 0.3.0 release

### Modifications

- Update changelog
- Update `VERSION` file
- Update `statble.txt` file

Author: wolfstudy

CHANGELOG.md

@@ -23,6 +23,31 @@
 
 All notable changes to this project will be documented in this file.
 
+[0.3.0] 2020-11-11
+
+## Feature
+
+* Support retry letter topic in Go client, see [PR-359](https://github.com/apache/pulsar-client-go/pull/359).
+* Support limit the retry number of reconnectToBroker, see [PR-360](https://github.com/apache/pulsar-client-go/pull/360).
+* Support key shared policy in Go client, see [PR-363](https://github.com/apache/pulsar-client-go/pull/363).
+* Add schema logic in producer and consumer, see [PR-368](https://github.com/apache/pulsar-client-go/pull/368).
+
+
+## Improve
+
+* Fix panic on receiverQueueSize set to `-1`, see [PR-361](https://github.com/apache/pulsar-client-go/pull/361).
+* Fix may lead to panic test case, see [PR-369](https://github.com/apache/pulsar-client-go/pull/369).
+* Send delay message individually even batching is enabled, see [PR-372](https://github.com/apache/pulsar-client-go/pull/372).
+* Fixed buffer resize when writing request on connection, see [PR-374](https://github.com/apache/pulsar-client-go/pull/374).
+* Fixed deadlock in DLQ ack processing, see [PR-375](https://github.com/apache/pulsar-client-go/pull/375).
+* Fix deadlock when connection closed, see [PR-376](https://github.com/apache/pulsar-client-go/pull/376).
+* Fix producer deadlock after write failure, see [PR-378](https://github.com/apache/pulsar-client-go/pull/378).
+* Fix maxMessageSize not effective even if aligned with broker, see [PR-381](https://github.com/apache/pulsar-client-go/pull/381).
+* Update default router to switch partition on all batching thresholds, see [PR-383](https://github.com/apache/pulsar-client-go/pull/383).
+* Replaced `github.com/DataDog/zstd` with `github.com/datadog/zstd`, see [PR-385](https://github.com/apache/pulsar-client-go/pull/385).
+* Fix retry policy not effective with non-FQDN topics, see [PR-386](https://github.com/apache/pulsar-client-go/pull/386).
+
+
 [0.2.0] 2020-08-28
 
 ## Feature

VERSION

@@ -1,3 +1,3 @@
 // This version number refers to the currently released version number
 // Please fix the version when release.
-v0.2.0
+v0.3.0

stable.txt

@@ -1,3 +1,3 @@
 // This version number refers to the current stable version, generally is `VERSION - 1`.
 // Please fix the version when release.
-v0.2.0
+v0.3.0