`Repository.create_label()` should allow `color` to be unspecified

[jwodder]

The Repository.create_label() method should support being called without a color argument. The GitHub API accepts label creation requests that do not specify a color; the resulting labels are assigned random colors.

[amnuts]

Definitely the case for the 2022-11-28 version of the REST API?

Looking at what Repository.create_label() calls, https://docs.github.com/en/rest/issues/labels?apiVersion=2022-11-28#create-a-label, it states:

Creates a label for the specified repository with the given name and color. The name and color parameters are required.

Unless you were seeing it somewhere else that it's optional?

[jwodder]

Despite what the API docs say, GitHub will accept a request to create a label that omits the "color" field, though it seems that the color will then always be set to some fixed grey value rather than being randomized.