build documentation container in CI

Author: rmorshea

.github/workflows/test.yml

@@ -66,3 +66,14 @@ jobs:
           npm install
           npm test
           npm run build
+  test-documentation-image:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out src from Git
+        uses: actions/checkout@v2
+      - name: Get history and tags for SCM versioning to work
+        run: |
+          git fetch --prune --unshallow
+          git fetch --depth=1 origin +refs/tags/*:refs/tags/*
+      - name: Build Docker Image
+        run: docker build . --file docs/Dockerfile