Update checkout to v4

Author: Xaeroxe

.github/workflows/powershell.yml

@@ -15,6 +15,6 @@ jobs:
     env:
       GH_TOKEN: ${{ secrets.GH_TOKEN }}
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - run: ./check.ps1
         shell: pwsh