update actions/checkout to v4

Author: antonok-edm

.github/workflows/ci.yml

@@ -25,7 +25,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Cargo build 'adblock' package
         run: cargo build --all-features --all-targets