get the current repo but do not delete the build files

.github/workflows/linter.yml

@@ -81,6 +81,11 @@ jobs:
     container:
       image: ghcr.io/genspectrum/lapis-silo-linter-dependencies:commit-${{ github.sha }}
     steps:
+      - uses: actions/checkout@v4
+        with:
+          path: /src
+          clean: false
+
       - shell: bash
         working-directory: /src
         name: Configure and run clang-tidy on changed files