add a github actions CI workflow

.github/workflows/ci.yml

@@ -0,0 +1,76 @@
+# badge: https://github.com/bepasty/bepasty-server/workflows/CI/badge.svg?branch=master
+
+name: CI
+
+on:
+  push:
+    branches: [ master ]
+    paths:
+    - '**.py'
+    - '**.yml'
+    - '**.cfg'
+    - '**.ini'
+    - 'requirements.d/*'
+    - '!docs/**'
+  pull_request:
+    branches: [ master ]
+    paths:
+    - '**.py'
+    - '**.yml'
+    - '**.cfg'
+    - '**.ini'
+    - 'requirements.d/*'
+    - '!docs/**'
+
+jobs:
+  lint:
+
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python
+      uses: actions/setup-python@v2
+      with:
+        python-version: 3.8
+    - name: Lint with flake8
+      run: |
+        pip install flake8
+        flake8 src scripts conftest.py
+
+  pytest:
+
+    needs: lint
+    env:
+      # Configure pkg-config to use OpenSSL from Homebrew
+      PKG_CONFIG_PATH: /usr/local/opt/[email protected]/lib/pkgconfig
+      TOXENV: ${{ matrix.toxenv }}
+
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        # just fetching 1 commit is not enough for setuptools-scm, so we fetch all
+        fetch-depth: 0
+    - name: Set up Python
+      uses: actions/setup-python@v2
+      with:
+        python-version: 3.5
+    - name: Install Python requirements
+      run: |
+        python -m pip install --upgrade pip setuptools wheel
+        pip install -r requirements.d/development.txt
+    - name: run pytest via tox
+      run: |
+        tox --skip-missing-interpreters
+    - name: Upload coverage to Codecov
+      uses: codecov/codecov-action@v1
+      env:
+        OS: ${{ runner.os }}
+        python: ${{ matrix.python-version }}
+      with:
+        token: ${{ secrets.CODECOV_TOKEN }}
+        env_vars: OS, python