add semver carret to the 2.0.0 angular deps

[mseemann]

... make sure this package will run with all versions < 3.0.0

[grizzm0]

I would rather use ~2.0.0 instead of ^2.0.0 as 2.1.0 is allowed minor breaks.

[mseemann]

they promised they will not :)

http://angularjs.blogspot.de/:
the MAJOR version gets incremented when incompatible API changes are made to stable APIs,
the MINOR version gets incremented when backwards-compatible functionality are added,
the PATCH version gets incremented when backwards-compatible bug are fixed.