Workaround lack of support for slashes in bundlewatch

bundlewatch/bundlewatch#422

.github/workflows/bundlewatch.yml

@@ -10,19 +10,23 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
-      with:
-        fetch-depth: 2
-    - run: git checkout HEAD^
 
     - name: Install npm dependencies
       run: npm ci
 
     - name: Build
       run: npm run build
 
+    # bundlewatch/ci-env does not support slashes in branch names, so we need to parse ref by ourselves to provide CI_BRANCH
+    - name: Extract branch name
+      shell: bash
+      run: echo "::set-env name=BRANCH_NAME::$(echo ${GITHUB_REF#refs/heads/})"
+      id: extract_branch
+
     - name: Run bundlewatch
       run: npx bundlewatch
       env:
         BUNDLEWATCH_GITHUB_TOKEN: ${{ secrets.BUNDLEWATCH_GITHUB_TOKEN }}
         CI_COMMIT_SHA: ${{ github.event.pull_request.head.sha }}
+        CI_BRANCH: ${{ env.BRANCH_NAME }}
         CI_BRANCH_BASE: ${{ github.base_ref || 'trunk' }}