Migrate from Travis to GitHub Actions

.github/actions/initialize/action.yml

@@ -0,0 +1,13 @@
+name: 'Initialize'
+description: 'Checkout repo and install dependencies'
+runs:
+  using: "composite"
+  steps:
+    - name: Check out repository code
+      uses: actions/checkout@v4
+    - name: Upgrade pip
+      run: python -m pip install --upgrade pip
+      shell: bash
+    - name: Install documentation building framework
+      run: pip install mkdocs
+      shell: bash

.github/workflows/deploy-docs.yml

@@ -0,0 +1,47 @@
+name: Build and Deploy Docs
+
+on:
+  pull_request:
+    types:
+      - closed
+    branches:
+      - main
+      - master
+
+# Sets permissions of the GITHUB_TOKEN to allow deployment to GitHub Pages
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+# Allow only one concurrent deployment, skipping runs queued between the run in-progress and latest queued.
+# However, do NOT cancel in-progress runs as we want to allow these production deployments to complete.
+concurrency:
+  group: "pages"
+  cancel-in-progress: false
+
+jobs:
+  deploy:
+    if: github.event.pull_request.merged == true
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Initialize the environment
+        uses: ./.github/actions/initialize
+        with:
+          documentation: 'true'
+      - name: Build Docs
+        run: |
+            mkdocs build --strict --verbose
+            touch .site/.nojekyll
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: '.site'
+      - name: Setup Pages
+        uses: actions/configure-pages@v5
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4

.github/workflows/repo-checks.yml

@@ -0,0 +1,19 @@
+name: PR Checks
+
+on:
+  pull_request:
+    branches:
+      - main
+      - master
+
+jobs:
+  check-docs:
+    name: Check docs for warnings
+    runs-on: ubuntu-latest
+    steps:
+      - name: Initialize the environment
+        continue-on-error: true
+        uses: ./.github/actions/initialize
+      - name: Build Docs
+        continue-on-error: true
+        run: mkdocs build --strict --verbose

CONTRIBUTING.md

@@ -9,7 +9,8 @@ We have adopted the following style guidelines:
 
 ## Deploying docs to Github Pages Site
 
-We're currently using TravisCI to deploy to Github Pages. To update the GH_SECRET_TOKEN environment variable referenced in the `.travis.yml` file, follow the [TravisCI documentation](https://docs.travis-ci.com/user/deployment/pages/). Only master docs can be deployed to the documentation site.
+We're currently using GitHub Actions to deploy to Github Pages.
+The docs on the master branch are automatically deployed to the documentation site.
 
 ## Building the Docs Locally