ci(tools): update dependabot/fetch-metadata action to v3

Author: renovate[bot]

.github/workflows/automerge.yml

@@ -29,7 +29,7 @@ jobs:
           permission-issues: write
 
       - name: Fetch metadata
-        uses: dependabot/fetch-metadata@v2
+        uses: dependabot/fetch-metadata@v3
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}