Add CI test build (#253)

Signed-off-by: Douglas Stebila <[email protected]>

.github/workflows/build.yml

@@ -0,0 +1,22 @@
+name: Build Jekyll site
+
+on:
+  push
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # pin@v4
+      - name: Pull liboqs submodule
+        run: git submodule update --init
+      - name: Setup Ruby
+        # https://github.com/ruby/setup-ruby/releases/tag/v1.207.0
+        uses: ruby/setup-ruby@4a9ddd6f338a97768b8006bf671dfbad383215f4
+        with:
+          ruby-version: '3.1' # Not needed with a .ruby-version file
+          bundler-cache: true # runs 'bundle install' and caches installed gems automatically
+          cache-version: 0 # Increment this number if you need to re-download cached gems
+      - name: Build with Jekyll
+        run: bundle exec jekyll build