Update to compile-sketch workflow to actions/checkout@v4

Author: PaulZC

.github/workflows/compile-sketch.yml

@@ -86,7 +86,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Branch name
         run: echo running on branch ${GITHUB_REF##*/}