Revert "Configure Cirrus Branch Guard (#2492)" (#2496)

This reverts commit bc69693ef0ad08059b8884cab5ace1877837b9ab.
diff --git a/.github/workflows/branch-guard.yml b/.github/workflows/branch-guard.yml
deleted file mode 100644
index b40d1d6..0000000
--- a/.github/workflows/branch-guard.yml
+++ /dev/null
@@ -1,17 +0,0 @@
-on:
-  pull_request: # to update newly open PRs or when a PR is synced
-  check_suite: # to update all PRs upon a Check Suite completion
-    type: ['completed']
-  
-name: Branch Guard
-jobs:
-  branch-guard:
-    name: Branch Guard
-    if: github.event.check_suite.head_branch == 'master' || github.event.pull_request.base.ref == 'master'
-    runs-on: ubuntu-latest
-    steps:
-    - uses: cirrus-actions/branch-guard@v1.2
-      with:
-        appsToCheck: Cirrus CI # or any other App name (can be a comma separated list of names)
-      env:
-        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}