run markdownlint on changed_files

Author: vjdhama

.github/workflows/markdown-lint.yml

@@ -7,13 +7,19 @@ on:
       - main
 
 jobs:
-  lint-blog-files:
-    name: Lint blog markdown files
+  lint:
     runs-on: ubuntu-latest
     steps:
-    - name: Check out code
-      uses: actions/checkout@v2
+    - uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
+    - uses: tj-actions/changed-files@v45
+      id: changed-files
+      with:
+        files: '**/*.md'
+        separator: ","
     - uses: DavidAnson/markdownlint-cli2-action@v17
+      if: steps.changed-files.outputs.any_changed == 'true'
       with:
-        config: '.markdownlint.json'
-        globs: 'content/blog/*.md'
+        globs: ${{ steps.changed-files.outputs.all_changed_files }}
+        separator: ","