Update .github/workflows/main.yml

Co-authored-by: Viktor Bozhinov <[email protected]>

.github/workflows/main.yml

@@ -12,7 +12,7 @@ jobs:
     steps:
       # Checkout code
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
 
       - name: Build and run ICAT Docker Compose stack
         run: docker compose up -d opensearch seed_opensearch scigateway-auth