chore(.github/workflows/pr_validation): enforce check

Signed-off-by: Thibault Camalon <[email protected]>

.github/workflows/pr_validation.yml

@@ -22,17 +22,17 @@ jobs:
         os: [ windows-latest ]
         python: [ "3.9" ]
     steps:
+      # Checkout not in working dir to ensure the imported module is the installed one
       - uses: actions/checkout@v3
+        with:
+          path: anywhere
       - uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python }}
       - name: Install dependencies
-        env:
-          GIT_TOKEN: ${{ secrets.GIT_TOKEN }}
-          GIT_USERNAME: ${{ secrets.GIT_USERNAME }}
         run: |
           python -m pip install --upgrade pip
-          pip install -e ".[all_extra]"
+          pip install -e "./anywhere/[all_extra]"
       - name: Test import successful
         run: |
           python -c "import fedeca"