Feature/GitHub commit status

[chris11-taylor-nttd]

This PR adds functionality to retrieve and set GitHub commit statuses from the CLI or within a pipeline.

# launch github commit status set --help                                                                                                                                              Usage: launch github commit status set [OPTIONS]

Options:
  --organization TEXT             GitHub organization containing your
                                  repository. Defaults to the launchbynttdata
                                  organization.
  --repository-name TEXT          Name of the repository to be updated.
                                  [required]
  --commit-hash TEXT              Full SHA1 hash of a Git commit.  [required]
  --target-url TEXT               The URL to link when setting a commit status
                                  message.
  --description TEXT              A short message to associate with the commit
                                  status.
  --context TEXT                  A string label to differentiate this status
                                  from the status of other systems.
  --status [error|failure|pending|success]
                                  The status to set on the commit.  [required]
  --help                          Show this message and exit.

# launch github commit status get --help
Usage: launch github commit status get [OPTIONS]

Options:
  --organization TEXT     GitHub organization containing your repository.
                          Defaults to the launchbynttdata organization.
  --repository-name TEXT  Name of the repository to be updated.  [required]
  --commit-hash TEXT      Full SHA1 hash of a Git commit.  [required]
  --context TEXT          A string label to differentiate this status from the
                          status of other systems.
  --help                  Show this message and exit.

# Set a "pending" status on a commit to indicate a CI run is in progress. 
# The "context" and "description" are displayed on the PR page, and the 
# "target URL" is linked through the "Details" button, allowing a user
# to link directly into a CI pipeline run:
launch github commit status set \
    --repository-name "tf-aws-module_primitive-api_gateway_v2" \
    --commit-hash "a87b67e7040ec3fc48c5e3c20f6f6f42b611c1b8" \
    --status pending \
    --target-url "https://launch.nttdata.com" \
    --context "ci/shared-aws-terraform-pipeline" \
    --description "Build in progress..."

---

# Set a "complete" status on a commit to allow the merge
# to proceed.
launch github commit status set \
    --repository-name "tf-aws-module_primitive-api_gateway_v2" \
    --commit-hash "a87b67e7040ec3fc48c5e3c20f6f6f42b611c1b8" \
    --status complete \
    --target-url "https://launch.nttdata.com" \
    --context "ci/shared-aws-terraform-pipeline" \
    --description "Build succeeded."

---

# Retrieve a commit status
launch github commit status get \
    --repository-name "tf-aws-module_primitive-api_gateway_v2" \
    --commit-hash "a87b67e7040ec3fc48c5e3c20f6f6f42b611c1b8" \
    --context "ci/shared-aws-terraform-pipeline"
success