build: use v2 of release-please-action

Author: bcoe

.github/workflows/release-please.yml

@@ -7,7 +7,7 @@ jobs:
   release-please:
     runs-on: ubuntu-latest
     steps:
-      - uses: GoogleCloudPlatform/release-please-action@v2.5.3
+      - uses: GoogleCloudPlatform/release-please-action@v2
         id: release
         with:
           token: ${{ secrets.GITHUB_TOKEN }}