Add pr-docs-check-container-ssr action.

Author: samsrabin

.github/workflows/pr-docs-check-container-ssr.yml

@@ -0,0 +1,16 @@
+name: "Pull Request Docs Check (Container, SSR Fork)"
+on: 
+- pull_request
+
+jobs:
+  docs:
+    runs-on: ubuntu-latest
+    container:
+      image: escomp/base:latest
+    steps:
+    - uses: actions/checkout@v1
+    - uses: samsrabin/sphinx-action@use-escomp-base-container
+      with:
+        docs-folder: "doc"
+        pre-build-command: "(cd doc && make fetch-images)"
+        build-command: "make html"