housekeeping: fail React flavor release if a step fails (via #5466)

* housekeeping: fail React flavor release if a step fails

* Update run.sh

flavors/swagger-ui-react/release/run.sh

@@ -1,9 +1,12 @@
 # Deploy `swagger-ui-react` to npm.
 
+# https://www.peterbe.com/plog/set-ex
+set -ex
+
 # Parameter Expansion: http://stackoverflow.com/questions/6393551/what-is-the-meaning-of-0-in-a-bash-script
 cd "${0%/*}"
 
-mkdir ../dist
+mkdir -p ../dist
 
 # Copy UI's dist files to our directory
 cp ../../../dist/swagger-ui.js ../dist