Add pull_request trigger for testing

Author: mbg

.github/workflows/update-proxy-release.yml

@@ -1,5 +1,8 @@
 name: Update dependency proxy release assets
 on:
+  pull_request:
+    branches:
+      - mbg/update-proxy-binaries # for testing
   workflow_dispatch:
     inputs:
       tag:
@@ -16,7 +19,7 @@ jobs:
       contents: write # needed to push the updated files
       pull-requests: write # needed to create the PR
     env:
-      RELEASE_TAG: ${{ inputs.tag }}
+      RELEASE_TAG: ${{ inputs.tag || 'codeql-bundle-v2.22.0' }}
     steps:
       - name: Install Node
         uses: actions/setup-node@v4