add docstring test

.github/workflows/qc_checks.yaml

@@ -125,6 +125,21 @@ jobs:
           invoke check-server
           coverage run -m unittest discover -s test/
 
+  docstyle:
+    name: Style [Python Docstrings]
+    runs-on: ubuntu-20.04
+
+    needs: pre-commit
+    continue-on-error: true
+
+    steps:
+      - name: Enviroment Setup
+        uses: inventree/inventree/.github/actions/setup@master
+        with:
+          install: true
+      - name: flake8
+        run: flake8 InvenTree
+
   coverage:
     name: Tests - DB [SQLite] + Coverage
     runs-on: ubuntu-20.04