Add support for go modules/dep and github action go project tests

[dougnukem]

Closes #2

• Adds support for new Action environment variable PROJECT_PATH to allow for a subdirectory in the workspace to be used as Go project root (useful when multiple go builds are in a single mono repo, or for testing within this action)

• Adds test projects

  • tests/projects/go_standard
  • tests/projects/go_modules
  • tests/projects/go_modules_vendor
    • Adds a lot of files under ./vendor

• Adds workflow actions to run those projects

  action "Test Go Modules" {
  uses = "./"
  env = {
  PROJECT_PATH = "./tests/projects/go_modules"
  IMPORT = "cedrickring/golang-action"
  }
  }

Using act local github action tool you can run the tests

$ act -a "Test Go Modules"
[Test Go Modules] docker build -t golang-action:3849038 /Users/ddaniels/dev/src/github.com/cedrickring/golang-action
[Test Go Modules] docker run image=golang-action:3849038 entrypoint=[] cmd=[]
go: finding github.com/spf13/viper v1.3.1
go: downloading github.com/mitchellh/go-homedir v1.1.0
go: downloading github.com/spf13/cobra v0.0.3
...
ok      github.com/cedrickring/golang-action/tests/projects/go_modules  0.007s
?       github.com/cedrickring/golang-action/tests/projects/go_modules/cmd  [no test files]

[dougnukem]

@cedrickring yeah adding support for dep ensure makes sense if we detect the presence of a Gopkg.toml

[dougnukem]

@cedrickring added support and tests for Go projects that use dep (e.g. presence of a Gopkg.toml and also if the dep dependencies are vendored ->/vendor)

Also squashed the commits to cleanup the git history.

[dougnukem]

@cedrickring cleaned up those debug echo statements