ci: pin version to commit SHA

Author: Flashky

.github/workflows/enable-automerge.yml

@@ -27,7 +27,7 @@ jobs:
 
       - name: Obtain Dependabot Metadata
         id: metadata
-        uses: dependabot/[email protected]
+        uses: dependabot/fetch-metadata@08eff52bf64351f401fb50d4972fa95b9f2c2d1b #v2.4.0
         with:
           github-token: "${{ secrets.GITHUB_TOKEN }}"