Migrate from Travis-CI to GitHub Actions

.github/workflows/schedule.yml

@@ -0,0 +1,20 @@
+---
+name: Scheduled Site Tests
+on:  # yamllint disable-line rule:truthy
+  schedule:
+    - cron: "0 0 1 * *"  # Monthly
+jobs:
+  Tests:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          ref: gh-pages
+      - run: >-
+          docker create -t
+          --name yadm-website
+          --entrypoint test/validate
+          yadm/jekyll:2019-10-17;
+          docker cp ./ yadm-website:/srv/jekyll
+      - name: Test Site
+        run: docker start yadm-website -a

.github/workflows/test.yml

@@ -0,0 +1,16 @@
+---
+name: Tests
+on:  # yamllint disable-line rule:truthy
+  - push
+  - pull_request
+  - workflow_dispatch
+jobs:
+  Tests:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Tests
+        run: >-
+          docker run -t --rm
+          -v "$PWD:/yadm:ro"
+          yadm/testbed:2020-07-08

.travis.yml

@@ -1,8 +0,0 @@
----
-language: minimal
-services:
-  - docker
-before_install:
-  - docker pull yadm/testbed:2020-07-08
-script:
-  - docker run -t --rm -v "$PWD:/yadm:ro" yadm/testbed:2020-07-08