Configure the default user-agent for Telemetry purposes

[mridang]

Which Problems Are Solved

• The SDK did not include a default User-Agent header, limiting tracking of SDK usage.
• The semantic release configuration did not automatically update the version in the dedicated version file.

How the Problems Are Solved

• Default User-Agent: Added a default User-Agent in the SDK’s configuration which includes the SDK version, language identifier, language version, operating system, and architecture.

  Python example:

  import platform
  from zitadel_client.version import Version
  
  USER_AGENT = f"zitadel-client/{Version.VERSION} (lang=python; lang_version={platform.python_version()}; os={platform.system()}; arch={platform.machine()})".lower()

  For other languages, use a similar approach that gathers runtime details as needed.

• Semantic Release Update: Updated the release configuration to bump the version in the version file automatically.

• API Client Update: Modified the API client to set its HTTP User-Agent header based on the configuration’s user_agent property.

Additional Changes

• Added tests to verify that the default User-Agent is correctly set and can be updated.
• Refactored code to remove hardcoded User-Agent values, relying on configuration defaults.
• Updated documentation and comments for clarity.

Additional Context

None.