Move EndShipper to general availability

[nwithan8]

Description

• Copy EndShipper to main namespace
• Mark beta EndShipper as deprecated
• Update unit tests

Testing

• Unit tests for EndShipper updated and passing

Pull Request Type

Please select the option(s) that are relevant to this PR.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Improvement (fixing a typo, updating readme, renaming a variable name, etc)

[Justintime50]

We need to update the require_once line in the /lib/easypost.php file for users that manually require our library, I'm not seeing that here.

[nwithan8]

We need to update the require_once line in the /lib/easypost.php file for users that manually require our library, I'm not seeing that here.

Thanks, I knew there was something along those lines, couldn't remember what.

Addressed

[Justintime50]

Thanks, I knew there was something along those lines, couldn't remember what.

May be good to ask next time then 😅