Fix dependabot_pr workflow (#5353)

Signed-off-by: Craig Perkins <cwperx@amazon.com>

Author: cwperks

.github/workflows/dependabot_pr.yml

@@ -21,6 +21,7 @@ jobs:
         uses: actions/checkout@v4
         with:
           token: ${{ steps.github_app_token.outputs.token }}
+          ref: ${{ github.head_ref }}
 
       # See please https://docs.gradle.org/8.10/userguide/upgrading_version_8.html#minimum_daemon_jvm_version
       - name: Set up JDK 21