Confluent-kafka-helpers

Changes
- Update dependencies

Changes
- [Fix memory leak 69](https://github.com/fyndiq/confluent_kafka_helpers/pull/69)

Fixes:
- Upgrade `confluent-kafka` to `1.7.0` (68)

Fixes:
- Upgrade `confluent-kafka` to `1.6.1` (63)
- Pass forward `**kwargs` on AvroConsumer/AvroProducer (65)
- Update default config for provider to better fit with enable.idempotence (66)

Features:
- Add opentracer support (46)

Fixes:
- Support non-bytes message headers (57)

Minor:
- Add feature toggle for Datadog metrics (52)
- Update default consumer and producer configs (54)