Add dep v0.3.0, remove dep v0.2.1
Add dep v0.3.0, remove dep v0.2.1

source url: https://github.com/golang/dep/archive/v0.3.0.tar.gz
source sha256: 7d816ffb14f57c4b01352676998a8cda9e4fb24eaec92bd79526e1045c5a0c83

[#150925828]
[#150966936]

cloudfoundry/go-buildpack,cloudfoundry/go-buildpack,cloudfoundry/go-buildpack