don't merge changes from main branch

.github/workflows/main-build.yml

@@ -13,9 +13,13 @@ jobs:
   build-push-container:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - name: Checkout code
+        uses: actions/checkout@v3
         with:
-          fetch-depth: "0" # Per https://github.com/ignite/cli/issues/1674#issuecomment-1144619147
+          # Pull the gitsha of the PR, and don't merge changes from main automatically.
+          ref: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || github.sha }}
+          # Per https://github.com/ignite/cli/issues/1674#issuecomment-1144619147
+          fetch-depth: "0"
 
       - name: install ignite
         run: make ignite_install