Update dependabot/fetch-metadata action to v2

Author: renovate[bot]

.github/workflows/auto-merge.yml

@@ -31,7 +31,7 @@ jobs:
       - name: Fetch Dependabot metadata
         if: github.actor == 'dependabot[bot]'
         id: metadata
-        uses: dependabot/fetch-metadata@v1
+        uses: dependabot/fetch-metadata@v2
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}