AUTH-5460 Add ping_env_id to cloudflare-go

[ajholland]

Description

ping_env_id is supported as a field in our api already for the Ping identity provider connection
https://developers.cloudflare.com/api/operations/access-identity-providers-list-access-identity-providers

ping isn't currently supported in terraform, adding this field will allow it to be supported in terraform.
(This is the last one I have for now, I don't expect to add more of these in the short term).

Has your change been tested?

Screenshots (if appropriate):

Types of changes

• [ x] New feature (non-breaking change which adds functionality)

Checklist:

• [x ] My code follows the code style of this project.
• [x ] My change requires a change to the documentation.
• [x ] I have updated the documentation accordingly.
• [x ] I have added tests to cover my changes.
• [x ] All new and existing tests passed.
• [ x] This change is using publicly documented in cloudflare/api-schemas
  and relies on stable APIs.

[github-actions]

changelog detected ✅

[github-actions]

This functionality has been released in v0.77.0.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!