Upgrades actions/checkout

Author: ultimaweapon

.github/workflows/ci.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
     - name: Checkout source
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
     - name: Check code styles
       run: cargo fmt --check
     - name: Run Clippy