docs: update action for link check and fix one broken link (#1322)

fix: update action for link check and fix one broken link

Author: xuan-cao-swi

.github/workflows/ci-markdown-link.yml

@@ -2,16 +2,19 @@ name: Markdown Link Check
 
 on:
   pull_request:
+    paths:
+      - '**/*.md'
 
 jobs:
   markdown-link-check:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
 
-      - name: "Markdown Link Check"
-        uses: gaurav-nelson/github-action-markdown-link-check@v1
+      # equivalent cli: linkspector check
+      - name: Run linkspector
+        uses: umbrelladocs/action-linkspector@v1
         with:
-          config-file: '.markdown-link-check.json'
-          use-quiet-mode: 'yes'
-          use-verbose-mode: 'yes'
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          reporter: github-pr-review
+          fail_on_error: true

.markdown-link-check.json

@@ -32,7 +32,7 @@ end
 
 ## Examples
 
-Example usage of active_model_serializers can be seen in the `./example/active_model_serializers.rb` file [here](https://github.com/open-telemetry/opentelemetry-ruby-contrib/blob/main/instrumentation/active_model_serializers/example/active_model_serializers.rb)
+Example usage of active_model_serializers can be seen in the `./example/` folder [here](https://github.com/open-telemetry/opentelemetry-ruby-contrib/tree/main/instrumentation/active_model_serializers/example)
 
 ## How can I get involved?