chore: remove http options

CHANGELOG.md

@@ -1,8 +1,9 @@
 ## Unreleased (v7.0.0)
 * (Major): Python 3.10 or newer is required. Support for Python 3.8 and 3.9 has been dropped.
-* (Major): `UnleashClient` and `AsyncUnleashClient` take their settings as option groups: `identity=IdentityOptions(...)`, `http=HttpOptions(...)`, `mode=PollingOptions(...)` or `mode=StreamingOptions()`, and `metrics=MetricsOptions(...)`. Every argument after `url` and `app_name` is keyword-only. `ExperimentalMode` has been removed. See the [v7 migration guide](./v7_MIGRATION_GUIDE.md).
+* (Major): `UnleashClient` and `AsyncUnleashClient` take their settings as option groups: `identity=IdentityOptions(...)`, `mode=PollingOptions(...)` or `mode=StreamingOptions()`, and `metrics=MetricsOptions(...)`. Every argument after `url` and `app_name` is keyword-only. `ExperimentalMode` has been removed. See the [v7 migration guide](./v7_MIGRATION_GUIDE.md).
 * (Major): Settings can no longer be changed on an existing client. The `unleash_*` settings properties and the `strategy_mapping` and `connector_mode` properties have been removed, together with their setters.
-* (Major): The API token is passed as `api_key="<API token>"`. An `Authorization` header in `HttpOptions.headers` raises `ValueError`.
+* (Major): The API token is passed as `api_key="<API token>"`. An `Authorization` header in a transport's `headers` raises `ValueError`.
+* (Major): HTTP settings are set on the transport: `custom_headers` and `request_timeout` become `RequestsTransport(headers=..., timeout=...)`, or `AiohttpTransport(...)` for `AsyncUnleashClient`. `custom_options` has been removed: configure a `requests.Session` and pass `RequestsTransport(session)`. `request_retries` has been removed: a failed feature fetch is retried up to 3 times. The streaming connection doesn't use the transport: it is sent with the SDK's own headers and a 30s timeout.
 * (Major): The deprecated `environment` setting has been removed. The `environment` field of the evaluation context and the impact metrics `environment` label come from the API token, or are `"default"` when the token doesn't name one.
 * (Major): The `UnleashClient` and `AsyncUnleashClient` constructors raise `ValueError` if `url` is not an absolute http(s) URL with a host, for every client.
 * (Major): `initialize_client()` no longer raises when registration fails. A failed registration is logged and the client keeps running, the same way for both clients.