Added id, issuer, and serial_number to CustomHostnameSSL

[thienson-ho]

Adding additional SSL fields returned from the "List Custom Hostnames" Cloudflare response: id, issuer, and serial_number

Description

The three fields are added based on the response returned from the below documentation.
https://api.cloudflare.com/#custom-hostname-for-a-zone-list-custom-hostnames

Has your change been tested?

Updated unit tests to reflect changes.

Screenshots (if appropriate):

Types of changes

What sort of change does your code introduce/modify?

• 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 change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[jacobbednarz]

thank you @thienson-ho! 🍭