create experimental branch first

Author: tatomyr

.github/workflows/experimental-pr.yaml

@@ -13,14 +13,19 @@ jobs:
       pull-requests: write
 
     steps:
-      - name: Checkout the PR branch
+      - name: Checkout main branch
         uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.pull_request.head.ref }}
+          ref: main
           fetch-depth: 0
 
-      - name: Create/Update the experimental branch from main
-        run: git push -f origin main:refs/heads/experimental
+      - name: Create the experimental branch
+        run: git push origin main:refs/heads/experimental
+
+      - name: Checkout the PR branch
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
 
       - name: Create PR to experimental
         env: