Remove github_token from codebuild

[gweecl]

what

Remove github_token from codebuild module

why

• github_oauth_token causing conflict between codepipeline and codebuild where
  • In codepipeline, its used as a REAL github token value for Codepipeline Source config
  • In codebuild, its used as parameter store name
• codebuild module is not creating the parameter store resources, hence causing err during codebuild stage

  Phase context status code: Decrypted Variables Error Message: parameter does not exist: YOUR_GITHUB_TOKEN
  

• If github_token is needed, can manually put in using environment_variables variable

references

• Codebuild default variable for github token type: https://github.com/cloudposse/terraform-aws-codebuild/blob/dac7df9798eb4e7211e45c182f1b5a46c5218ae4/variables.tf#L103-L107
• Can manually pass via environment_variables variable: https://github.com/cloudposse/terraform-aws-codebuild/blob/dac7df9798eb4e7211e45c182f1b5a46c5218ae4/main.tf#L387-L403

[hans-d]

/terratest

[hans-d]

@gweecl Hi, can you update the pr so that it passes the tests? otherwise, it is likely to be closed due to staleness.