Remove TravisCI, add GitHub Actions

.github/workflows/tests_maybe_release.yml

@@ -0,0 +1,26 @@
+name: tests_maybe_release
+
+on:
+  push:
+  pull_request:
+  release:
+    types: [published]
+
+jobs:
+  tests_maybe_release:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+      - uses: actions/checkout@v1
+      - name: Lint code
+        run: make lint
+      - name: Run tests
+        run: |
+          make tests CODE_COVERAGE=1
+          bash <(curl -s https://codecov.io/bash)
+      - name: Release
+        if: ${{ github.event_name == 'release' }}
+        run: make publish VERSION=${{ github.event.release.tag_name }} DOCKER_USER=${{ secrets.DOCKER_USER }} DOCKER_PASSWORD=${{ secrets.DOCKER_PASSWORD }}