Old Go version

[Bo0mer]

Hello,

I've been using this application to showcase some features of the CF platform. Since it uses Go version 1.6.4 which is quite old now (1.10rc1 was announced some days ago), the buildpack logs is full of warnings and errors which is frustrating to newcomers to the platform:

   -----> Go Buildpack version 1.8.14
   -----> Checking Godeps/Godeps.json file
   -----> Installing godep v79
          Download [https://buildpacks.cloudfoundry.org/dependencies/godep/godep-v79-linux-x64-9e37ce0f.tgz]
   -----> Installing glide v0.13.1
          Download [https://buildpacks.cloudfoundry.org/dependencies/glide/glide-v0.13.1-linux-x64-4959fbf0.tgz]
   -----> Installing dep v0.3.2
          Download [https://buildpacks.cloudfoundry.org/dependencies/dep/dep-v0.3.2-linux-x64-8910d5c1.tgz]
   -----> Installing go 1.6.4
          Download [https://buildpacks.cloudfoundry.org/dependencies/go/go1.6.4.linux-amd64-342b0164.tar.gz]
          **WARNING** go 1.6.x will no longer be available in new buildpacks released after 2017-02-16.
          See: https://golang.org/doc/devel/release.html
          **WARNING** Installing package '.' (default)
   -----> Running: godep go install -tags cloudfoundry -buildmode pie .
   godep: WARNING: Godep workspaces (./Godeps/_workspace) are deprecated and support for them will be removed when go1.8 is released.
   godep: WARNING: Go version (go1.6) & $GO15VENDOREXPERIMENT= wants to enable the vendor experiment, but disabling because a Godep workspace (Godeps/_workspace) exists

Please consider updating the Go version. If you're OK with that, I'll be happy to provide a merge request.
Thanks for your awesome work!