build(java): update autorelease script

Noticed the workflow was getting skipped on all the release PRs. Updating due to recent update in release-please branch name.

Source-Author: Stephanie Wang <[email protected]>
Source-Date: Tue Feb 9 19:10:03 2021 -0500
Source-Repo: googleapis/synthtool
Source-Sha: 2414b817065726eae0bc525346c7e874f969369d
Source-Link: googleapis/synthtool@2414b81

Author: yoshi-automation

.github/workflows/auto-release.yaml

@@ -4,7 +4,7 @@ name: auto-release
 jobs:
   approve:
     runs-on: ubuntu-latest
-    if: contains(github.head_ref, 'release-v')
+    if: contains(github.head_ref, 'release-please')
     steps:
     - uses: actions/github-script@v3
       with:
@@ -16,7 +16,7 @@ jobs:
             return;
           }
 
-          // only approve PRs like "chore: release <release version>"
+          // only approve PRs like "chore(master): release <release version>"
           if ( !context.payload.pull_request.title.startsWith("chore(master): release") ) {
             return;
           }

synth.metadata

@@ -11,7 +11,7 @@
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "692715c0f23a7bb3bfbbaa300f7620ddfa8c47e5"
+        "sha": "2414b817065726eae0bc525346c7e874f969369d"
       }
     }
   ],