v1.21.0

This release includes an enhancement to the Apache Kafka data source, and updates the OPA version used in Enterprise OPA to v0.64.1, and brings in various dependency bumps.

Kafka data source: prometheus metrics (per-instance)

Each instance of the Kafka data plugin now contributes a bunch of Prometheus metrics to the global metrics endpoint:

kafka_MOUNTPOINT_METRIC

Where MOUNTPOINT is foo:bar for a Kafka data plugin configured to manage data.foo.bar. (The Prometheus metrics naming restrictions forbid
both "." and "/" in metric names.)

Kafka data source: logging enhancements

When run with log level "debug", the low-level Kafka logs are overwhelming most of the times.
They are now suppressed by default, and can be inspected when running with the environment variable EOPA_KAFKA_DEBUG, like:

EOPA_KAFKA_DEBUG=1 eopa run -s -ldebug -c eopa.yaml transform.rego

In addition to that, the consumer group (if configured) is now logged when the data source plugin is initiated.
Also, new key/value fields were introduced to read the batch size and transformation time from the logs more easily.

VM: builtin function json.unmarshal is now natively implemented

This improves the performance by lowered data conversion overheads.
This, too, benefits Kafka transforms because they always include a json.unmarshal call.