dashboard/app: tag 1.3 release
dashboard/app: tag 1.3 release

R=adg
TBR=adg
CC=golang-codereviews
https://golang.org/cl/102590043

golang/build,proppy/build,golang/build,evandbrown/build,proppy/build,evandbrown/build,golang/build,golang/build,evandbrown/build,proppy/build,proppy/build