ci: Replace Travis CI with GitHub Actions

* Add a GitHub Actions workflow largely borrowed from
  <https://github.com/tox-dev/tox-gh>.
* Remove Travis CI config

Resolves #10

Author: bd808

.github/workflows/tox.yml

@@ -0,0 +1,42 @@
+name: tox
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+concurrency:
+  group: tox-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    name: test with ${{ matrix.py }} on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        py:
+          - "3.7"
+          - "3.8"
+          - "3.9"
+          - "3.10"
+          - "3.11"
+        os:
+          - ubuntu-latest
+          # - macos-latest
+          # - windows-latest
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+      - name: Setup python for test ${{ matrix.py }}
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.py }}
+      - name: Install tox
+        run: python -m pip install tox-gh>=1.2
+      - name: Setup test suite
+        run: tox -vv --notest
+      - name: Run test suite
+        run: tox --skip-pkg-install

.travis.yml

@@ -1,14 +1,13 @@
 [tox]
 minversion=1.6
 skipsdist=True
-envlist=flake8,py27,py34,py35,py36,py37,docs
+envlist=flake8,py37,py38,py39,py310,py311,docs
 
 [testenv]
 deps=
     -r{toxinidir}/requirements.txt
     coverage
     nose
-    py27: mock
 setenv=
     PYTHONDONTWRITEBYTECODE=true
 commands=