Dump Travis CI and move to GitHub Actions.

.github/workflows/release.yml

@@ -0,0 +1,38 @@
+---
+# This workflow requires a GALAXY_API_KEY secret present in the GitHub
+# repository or organization.
+#
+# See: https://github.com/marketplace/actions/publish-ansible-role-to-galaxy
+# See: https://github.com/ansible/galaxy/issues/46
+
+name: Release
+'on':
+  push:
+    tags:
+      - '*'
+
+defaults:
+  run:
+    working-directory: 'geerlingguy.docker'
+
+jobs:
+
+  release:
+    name: Release
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out the codebase.
+        uses: actions/checkout@v2
+        with:
+          path: 'geerlingguy.docker'
+
+      - name: Set up Python 3.
+        uses: actions/setup-python@v2
+        with:
+          python-version: '3.x'
+
+      - name: Install Ansible.
+        run: pip3 install ansible-base
+
+      - name: Trigger a new import on Galaxy.
+        run: ansible-galaxy role import --api-key ${{ secrets.GALAXY_API_KEY }} $(echo ${{ github.repository }} | cut -d/ -f1) $(echo ${{ github.repository }} | cut -d/ -f2)