0.9.2: Greater tolerance for badly encoded headers

This version corrects the service's behavior when it encounters header values that aren't encoded in UTF-8. Previously, the whole search request would fail, now it'll just substitute the offending value with "<unsupported encoding>" and continue.

[FIX] Issue where a badly encoded header value would fail the whole search request
[MAINTENANCE] The Python and Alpine versions of the Docker have been raised to 3.9.1 and 3.12 respectively
[MAINTENANCE] The Python dependencies have been bumped to their latest versions

Note: The Kafka API version default value has been raised to 2.1.1