Jekyll smoke test issue fix (#1298)

Author: Mathiyarasy

src/jekyll/.devcontainer/Dockerfile

@@ -16,6 +16,7 @@ RUN gem update --system
 
 # https://github.com/ntkme/sass-embedded-host-ruby/issues/130
 RUN gem install sass-embedded -v 1.62.1
+RUN gem install jekyll-sass-converter -v 3.0.0
 RUN gem install bundler jekyll github-pages
 
 RUN chown -R "vscode:rvm" "/usr/local/rvm/" \