chore: update auto-release script to fix breaking changes in v5 (#1350)

Author: Neenu1995

synthtool/gcp/templates/java_library/.github/workflows/auto-release.yaml

@@ -37,7 +37,7 @@ jobs:
  }
 
  // only approve PRs with pom.xml and versions.txt changes
- const filesPromise = github.pulls.listFiles.endpoint({
+ const filesPromise = github.rest.pulls.listFiles.endpoint({
  owner: context.repo.owner,
  repo: context.repo.repo,
  pull_number: context.payload.pull_request.number,
@@ -69,7 +69,7 @@ jobs:
  return;
  }
 
- const promise = github.pulls.list.endpoint({
+ const promise = github.rest.pulls.list.endpoint({
  owner: context.repo.owner,
  repo: context.repo.repo,
  state: 'open'
@@ -86,7 +86,7 @@ jobs:
  }
 
  // approve release PR
- await github.pulls.createReview({
+ await github.rest.pulls.createReview({
  owner: context.repo.owner,
  repo: context.repo.repo,
  body: 'Rubber stamped release!',
@@ -95,7 +95,7 @@ jobs:
  });
 
  // attach kokoro:force-run and automerge labels
- await github.issues.addLabels({
+ await github.rest.issues.addLabels({
  owner: context.repo.owner,
  repo: context.repo.repo,
  issue_number: context.payload.pull_request.number,