adding paths-ignore to workflow

.github/workflows/validate-flake8.yaml

@@ -5,6 +5,8 @@ on:
     branches:
        - 'main'
   pull_request:
+    paths-ignore:
+      - 'experiental_notebooks/**'
     types:
       - 'opened'
       - 'synchronize'
@@ -27,7 +29,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4 # changed from v3 to v4
+        uses: actions/checkout@v3
 
       - name: Validate notebooks
         uses: mhitza/[email protected]