Zswag

This release fixes additional-headers parameter passing to httplib for both the Python and C++ client.

This release improves the usability of zswag on macOS:

* Removed absolute libpython dependency path.
* Removed libbrotli dependency.
* Now bundling OpenSSL dependency.

Bugfix for `zswag.gen` to emit compliant nested parameter names.

Adding `HTTPError` python exception.

Small patch release, adding zserio Enum support and more robust request struct processing.

**First full-featured release, including the following components:**

- [x] Generic Python and C++ OpenAPI clients 🤖
- [x] Flask/Connexion-based OpenAPI Server 🧮
- [x] OpenAPI Generator CLI 🐍
- [x] Credential management 🔐
- [x] URL-based passing of scalar and scalar-array zserio request fields via OpenAPI 🌍