ci: add GitHub Actions workflow with ruff, black, mypy

.github/workflows/ci.yml

@@ -0,0 +1,48 @@
+name: CI
+
+on:
+  push:
+    branches: ["main"]
+  pull_request:
+    branches: ["main"]
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.9", "3.10", "3.11", "3.12"]
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -e ".[dev]"
+
+      - name: Lint with ruff
+        run: |
+          ruff check genpass/
+
+      - name: Check formatting with black
+        run: |
+          black --check genpass/
+
+      - name: Type check with mypy
+        run: |
+          mypy genpass/
+
+      - name: Test CLI
+        run: |
+          genpass --lower --upper --digits --symbols
+          genpass -l 20 -n 3
+          genpass --no-ambiguous --entropy