Setup mage for post dependabot action (#4012)

.github/workflows/post-dependabot.yml

@@ -22,6 +22,10 @@ jobs:
         with:
           go-version-file: .go-version
 
+      - uses: magefile/mage-action@v3
+        with:
+          install-only: true
+
       - name: update NOTICE.txt
         run: make notice
 
@@ -38,3 +42,20 @@ jobs:
           git remote set-url origin https://x-access-token:${{ secrets.GITHUB_TOKEN }}@github.com/${{ github.repository }}
           git commit -m "Update NOTICE.txt"
           git push
+
+      - name: update otel README.md
+        run: mage otel:readme 
+
+      - name: check for modified otel README.md
+        id: otel-readme-check
+        run: echo "modified=$(if git diff-index --quiet HEAD -- internal/pkg/otel/README.md; then echo "false"; else echo "true"; fi)" >> $GITHUB_OUTPUT
+
+      - name: commit otel README.md
+        if: steps.otel-readme-check.outputs.modified == 'true'
+        run: |
+          git config --global user.name 'dependabot[bot]'
+          git config --global user.email 'dependabot[bot]@users.noreply.github.com'
+          git add internal/pkg/otel/README.md
+          git remote set-url origin https://x-access-token:${{ secrets.GITHUB_TOKEN }}@github.com/${{ github.repository }}
+          git commit -m "Update otel README.md"
+          git push