Update STYLE-GUIDE.md (#373)
Update STYLE-GUIDE.md (#373)

Add a rule for repeated fields.
istio/api,cloudfoundry-attic/api,rshriram/api,rshriram/api,istio/api,istio/api,cloudfoundry-attic/api,istio/api,cloudfoundry-attic/api,geeknoid/api,geeknoid/api,cloudfoundry-attic/api,geeknoid/api,rshriram/api,geeknoid/api,cloudfoundry-attic/api