Ccs-digitalmarketplace-apiclient

Add support for Python 3.12

Rename `conversation` methods to `communication` as this is the term we are using for the model and routes now

Add the API client methods for the conversation messages routes

Add new audit types for conversation messages

Allow for use with all currently maintained Python versions:
- 3.9
- 3.10
- 3.11

Note, because request-mock does not support 3.12 yet, neither can we.

Create the ccs-digitalmarketplace-apiclient from the original [digitalmarketplace-apiclient](https://github.com/Crown-Commercial-Service/digitalmarketplace-apiclient/pulls).

For all changes before this version, please see the [digitalmarketplace-apiclient CHANGELOG](https://github.com/Crown-Commercial-Service/digitalmarketplace-apiclient/blob/main/CHANGELOG.md).