Improve IDE autocompletion

[shenkimaro]

A typed or constant Class added. This class has all available algorithms. In general, this type of class improves the autocomplete action in IDEs that only search for the class and already show the possibilities, avoiding text typing errors.

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

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[bshaffer]

Thank you for your contribution! This looks great. Consider updating the $supported_algs property in the JWT class as well! And also you'll need to sign the CLA for us to merge this.

Note: This can become an Enum class once support for PHP 8.0 and below is dropped

[bshaffer]

all of these indentations should be 4 spaces

Suggested change

	public const ES384 = 'ES384';
	public const ES384 = 'ES384';

[shenkimaro]

Hi @bshaffer. About "you'll need to sign the CLA", I try to push force updating the autor, but the CLA doesn't work yet. The error log says that there is a wrong autor, but through push force I already fixed it. Have you had issues with the CLA before?