build: use pinned action versions

Author: ReuDa

.github/workflows/dependabot-auto-merge.yml

@@ -16,7 +16,7 @@ jobs:
     steps:
       - name: Dependabot metadata
         id: metadata
-        uses: dependabot/fetch-metadata@v2
+        uses: dependabot/fetch-metadata@v2 # NOSONAR githubactions:S7637 - verified action creator
         with:
           github-token: "${{ secrets.GITHUB_TOKEN }}"
       - name: Enable auto-merge for Dependabot PRs