ci: add quality check workflow

.github/workflows/check-quality.yml

@@ -0,0 +1,31 @@
+name: qc (black/mypy/isort checks)
+
+on:
+  workflow_dispatch:
+  push:
+
+jobs:
+  analyse:
+    runs-on: ubuntu-latest
+    steps:
+      - name: checkout
+        uses: actions/checkout@v3
+
+      - name: install devbox  
+        uses: jetpack-io/devbox-install-action@v0.3.0
+
+      - name: install dependencies
+        run: devbox run poetry install
+
+      - name: install dependencies
+        id: build
+        run: devbox run poetry build
+        
+      - name: analyse with mypy
+        run: devbox run poetry run mypy surplus.py
+
+      - name: check for black formatting compliance
+        run: devbox run poetry run black --check surplus.py
+
+      - name: analyse isort compliance
+        run: devbox run poetry run isort --check surplus.py