ci: switch from Travis to GitHub Actions

Switched from Travis CI to GitHub Actions for the CI loop. This
necessitated dropping Python 3.4 as its no longer supported by the
dependencies of this project and not supported by upstream.

.github/workflows/main.yml

@@ -0,0 +1,35 @@
+name: Test
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: [2.7, 3.5, 3.6, 3.7]
+        os: [ubuntu-latest, macOS-latest]
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip setuptools
+          python -m pip install --upgrade tox
+
+      - name: Unit tests
+        run: |
+          tox -e py

setup.py

@@ -84,7 +84,6 @@ def run(self):
         "Programming Language :: Python :: 2",
         "Programming Language :: Python :: 2.7",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.4",
         "Programming Language :: Python :: 3.5",
         "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",