IMPORTANT THIS RELEASE IS BROKEN. Please use v2.0.14 which is identical with respect to the following changes.

Changes included this in release:

1. Fix map of maps https://github.com/ClickHouse/clickhouse-go/pull/554
2. Increase row limit to 1b - https://github.com/ClickHouse/clickhouse-go/pull/559
3. Fix deadlock on Close() https://github.com/ClickHouse/clickhouse-go/pull/548
4. Rename external to ext https://github.com/ClickHouse/clickhouse-go/pull/530