Add package install testing

.github/workflows/entrypoint_nightly.yml

@@ -29,11 +29,15 @@ jobs:
         with:
           python-version: "3.10"
       - name: Install requirements
-        run: python -m pip install --user build
+        run: python -m pip install --user build venv
       - name: Cleaning
         run : python setup.py clean
       - name: Build Exegol
         run: python -m build --sdist --outdir dist/ .
+      - name: Create testing venv
+        run: python -m venv vtest
+      - name: Install pip package
+        run: ./vtest/bin/pip install ./dist/*
       - name: Publish distribution 📦 to Test PyPI
         uses: pypa/gh-action-pypi-publish@release/v1
         if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags')