Remove `npm update`; add release-2.3 to branches
Remove `npm update`; add release-2.3 to branches

This command *should* do nothing immediately following an `npm install`, but causes failures due to `tslint` having a dependency on `typescript`.

Also add release-2.3 to our covered branches
alexeagle/TypeScript,TukekeSoft/TypeScript,microsoft/TypeScript,basarat/TypeScript,SaschaNaz/TypeScript,weswigham/TypeScript,donaldpipowitch/TypeScript,nojvek/TypeScript,Microsoft/TypeScript,chuckjaz/TypeScript,mihailik/TypeScript,Microsoft/TypeScript,SaschaNaz/TypeScript,mihailik/TypeScript,Eyas/TypeScript,chuckjaz/TypeScript,donaldpipowitch/TypeScript,minestarks/TypeScript,donaldpipowitch/TypeScript,TukekeSoft/TypeScript,minestarks/TypeScript,donaldpipowitch/TypeScript,kitsonk/TypeScript,SaschaNaz/TypeScript,Microsoft/TypeScript,basarat/TypeScript,kpreisser/TypeScript,synaptek/TypeScript,RyanCavanaugh/TypeScript,minestarks/TypeScript,chuckjaz/TypeScript,weswigham/TypeScript,kpreisser/TypeScript,kpreisser/TypeScript,kitsonk/TypeScript,nojvek/TypeScript,basarat/TypeScript,basarat/TypeScript,Eyas/TypeScript,Eyas/TypeScript,alexeagle/TypeScript,SaschaNaz/TypeScript,kitsonk/TypeScript,TukekeSoft/TypeScript,RyanCavanaugh/TypeScript,nojvek/TypeScript,synaptek/TypeScript,chuckjaz/TypeScript,nojvek/TypeScript,Eyas/TypeScript,RyanCavanaugh/TypeScript,alexeagle/TypeScript,mihailik/TypeScript,weswigham/TypeScript,synaptek/TypeScript,microsoft/TypeScript,synaptek/TypeScript,mihailik/TypeScript,microsoft/TypeScript