Added Environments API - GetAll list only feature

[semyon-p]

Let's add Environment API support.
#2329

As a 1st step I've implemented GetAll methods for Environments.

[nickfloyd]

Hey @semyon-p Thank you so much for the contributions here. If you get the chance, would you mind adding any test coverage that would be appropriate? If needed, you can look at what others have done before you here.

Thank you again for making things better! ❤️

[nickfloyd]

Overall, things look good here. Just a comment about the tests and also you'll need to add an interface to the Reactive Project - Octokit.Reactive.IObservableRepositoryDeployEnvironmentsClient we keep these in parity with the sync SDK APIs and interfaces. Let me know if you need any help with any of this! Thanks again for the contributions!

[semyon-p]

@nickfloyd hi!
I've added tests and IObservableRepositoryDeployEnvironmentsClient.
All tests are passed now. Please check.
I've made a small change in Octokit.Models.Request.ApiOptions class to become such kind of constructions work correctly:
if (options != ApiOptions.None)
{
//do something
}

[semyon-p]

@nickfloyd also I wanted to let you know, that I was trying to implement CreateEnvironment method but figured out, that API call described in the documentation does not work for me.
https://docs.github.com/en/rest/deployments/environments#create-or-update-an-environment
I've tried to test on a public personal repository.

DeleteEnvironment call works fine, by the way.
https://docs.github.com/en/rest/deployments/deployments#delete-a-deployment

Maybe I've done something wrong, but if you'll have some time please check it too. Maybe there is a bug in Github API itself.

[nickfloyd]

...also I wanted to let you know, that I was trying to implement CreateEnvironment method but figured out, that API call described in the documentation does not work for me.

Hey @semyon-p thanks for the updates! My guess on Create or Update environment is that since it uses the high REST PUT for both CREATE and UPDATE and does not support POST the verb being used was not the right one. IDK. It seems to work via direct call using PUT. I'll keep looking into it though - It's a good call out and I want to make sure we're not missing anything.

[mikebollandajw]

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