migrate to GH actions for deployment

.github/workflows/deploy.yml

@@ -0,0 +1,61 @@
+name: "Build and deploy"
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  build-and-check:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          submodules: recursive
+
+      - name: Setup Ruby
+        uses: ruby/setup-ruby@8575951200e472d5f2d95c625da0c7bec8217c42 # v1.161.0
+        with:
+          ruby-version: '3.1'
+          bundler-cache: true
+          cache-version: 0
+
+      - name: Setup Pages
+        id: pages
+        uses: actions/configure-pages@v5
+
+      - name: Build with Jekyll
+        run: bundle exec jekyll build --baseurl "${{ steps.pages.outputs.base_path }}"
+        env:
+          JEKYLL_ENV: production
+
+      - name: Check links
+        uses: lycheeverse/[email protected]
+        with:
+          # excluded # and ## as they used in the gallery
+          args: >
+            --no-progress --include-fragments --offline '_site' 
+            --exclude '##?$' 
+            
+      - name: Upload artifact
+        id: deployment
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: _site/      
+
+  deploy:
+    needs: build-and-check
+    permissions:
+      pages: write
+      id-token: write
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4          

Gemfile

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+source "https://rubygems.org"
+
+gem "jekyll", "~> 3.9.0"
+gem "minima", "~> 2.0"
+
+group :jekyll_plugins do
+  gem "jekyll-sitemap", "~> 1.4.0"
+  gem "jekyll-paginate-v2", "~> 3.0.0"
+  gem "jekyll-commonmark-ghpages", "~> 1.3.1"
+  gem "jekyll-feed", "~> 0.15.1"
+  gem "jekyll-redirect-from", "~> 0.16.0"
+end
+
+# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
+# and associated library.
+platforms :mingw, :x64_mingw, :mswin, :jruby do
+  gem "tzinfo", "~> 1.2"
+  gem "tzinfo-data"
+end
+
+# Performance-booster for watching directories on Windows
+gem "wdm", "~> 0.1.0", :platforms => [:mingw, :x64_mingw, :mswin]
+
+# kramdown v2 ships without the gfm parser by default. If you're using
+# kramdown v1, comment out this line.
+gem "kramdown-parser-gfm"
+