Remove the branch guard workflow (#3129)

.github/workflows/branch-guard.yml

@@ -1,37 +0,0 @@
-name: Branch guard
-
-on:
-  pull_request:
-    branches:
-      - dev
-      - main
-
-permissions:
-  contents: read
-
-jobs:
-  guard:
-    name: Reject branches forked from v2-dev
-    runs-on: ubuntu-latest
-    steps:
-      - name: Clone repository
-        uses: actions/checkout@v7
-        with:
-          fetch-depth: 0
-
-      - name: Check where the PR branch was forked from
-        env:
-          BASE: ${{ github.base_ref }}
-          HEAD_SHA: ${{ github.event.pull_request.head.sha }}
-        run: |
-          git fetch --quiet origin v2-dev "$BASE"
-          fork_point="$(git merge-base "$HEAD_SHA" origin/v2-dev)"
-
-          if git merge-base --is-ancestor "$fork_point" "origin/$BASE"; then
-            echo "OK: the branch was forked from $BASE."
-            exit 0
-          fi
-
-          echo "::error::This branch contains v2-dev history that is not on $BASE (fork point $fork_point)."
-          echo "::error::Merging it would pull the whole 2.0 delta into $BASE. Rebase onto origin/$BASE or retarget the PR to v2-dev."
-          exit 1