Bump peter-evans/enable-pull-request-automerge from 2 to 3 (#777)

Bumps [peter-evans/enable-pull-request-automerge](https://github.com/peter-evans/enable-pull-request-automerge) from 2 to 3.
- [Release notes](https://github.com/peter-evans/enable-pull-request-automerge/releases)
- [Commits](https://github.com/peter-evans/enable-pull-request-automerge/compare/v2...v3)

---
updated-dependencies:
- dependency-name: peter-evans/enable-pull-request-automerge
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/automerge.yml

@@ -11,7 +11,7 @@ jobs:
     if: ${{ github.actor == 'dependabot[bot]' }}
 
     steps:
-      - uses: peter-evans/enable-pull-request-automerge@v2
+      - uses: peter-evans/enable-pull-request-automerge@v3
         with:
           pull-request-number: ${{ github.event.pull_request.number }}
           merge-method: squash