Add Continuous Integration via Github Action

.github/workflows/ci.yml

@@ -0,0 +1,27 @@
+# This workflow will install Python dependencies, run tests and lint with a variety of Python versions
+# For more information see: https://help.github.com/actions/language-and-framework-guides/using-python-with-github-actions
+
+name: detect-secrets-ci
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+
+jobs:
+  main:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+        python: ['3.6', '3.7', '3.8', '3.9']
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: ${{ matrix.python }}
+    - run: python -m pip install --upgrade setuptools pip tox virtualenv
+    # Run tox only for the installed py version on the runner as outlined in the python matrix
+    # Ensures the correct py version is installed and tested as opposed to 'tox' which attempts to run for all py versions in tox.ini
+    - run: tox -e py
+    - run: tox -e mypy