Add ACTIONS_ALLOW_USE_UNSECURE_NODE_VERSION

Author: jmlapre

.github/workflows/PR_clang-format_test.yml

@@ -60,13 +60,15 @@ jobs:
 
 #   Checkout this users SST-core repo/branch
     - name: Checkout Users SST-Core source
-      uses: actions/checkout@v7
+      uses: actions/checkout@v4
+      env:
+        ACTIONS_ALLOW_USE_UNSECURE_NODE_VERSION: true
       with:
         path: ./sst-core_source
         ref: ${{ github.event.pull_request.head.sha }}
         # This is safe in a pull_request_target workflow because we are not
         # executing the code in any way.
-        allow-unsafe-pr-checkout: true
+        # allow-unsafe-pr-checkout: true
 
 #   Running the github action for clang format
     - name: Run Action clang-format-lint