re-add installing package non-editable and then linting ourselves

Author: mshafer-NI

.github/workflows/PR.yml

@@ -54,3 +54,12 @@ jobs:
         run: poetry install -v
       - name: Run tests
         run: poetry run pytest -v
+      - name: Install package into separate venv
+        run: |
+          python3 -m venv test_venv
+          source test_venv/bin/activate || test_venv\Scripts\activate
+          pip install .
+      - name: Lint our own pakage
+        run: |
+          source test_venv/bin/activate || test_venv\Scripts\activate
+          nps lint .