Merge pull request #753 from daiyam/fix-preview

fix markdown's preview

build.sh

@@ -15,6 +15,7 @@ if [[ "$SHOULD_BUILD" == "yes" ]]; then
   yarn valid-layers-check
 
   yarn gulp compile-build
+  yarn gulp compile-extension-media
   yarn gulp compile-extensions-build
   yarn gulp minify-vscode