update peer dependency to [email protected]

[IgorMinar]

npm WARN peerDependencies The peer dependency karma@>=0.9 included from karma-browserstack-launcher will no
npm WARN peerDependencies longer be automatically installed to fulfill the peerDependency 
npm WARN peerDependencies in npm 3+. Your application will need to depend on it explicitly.
\

blocks: angular/angular#5767

[zzo]

updating the peerDependency will not fix this issue as it's already pointing to a correct version >=.9 (which .13 is). This is just the warning that peerDependency stanzas are handled differently in npm@3 NOT that there's an issue.
I'm not sure why you are getting that warning. When I install karma-browserstack-launcher with karma .13 I don't see it ([email protected]) using node 5.1.0.
Do you see this warning on travis? Can you point me to it?