Add apt update step

.gitea/workflows/cppcheck.yml

@@ -8,6 +8,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+      - name: apt update
+        run: sudo apt update
       - uses: awalsh128/cache-apt-pkgs-action@v1
         with:
           packages: cppcheck