Update CHANGELOG for 0.6.0.
Update CHANGELOG for 0.6.0.

Add all changes since 0.5.0:
 - juttle 0.7.0 compatibility
 - New tests for sql adapters
 - Note on module resolution changes
 - Unit test fixes for juttle-engine, juttle-engine binary.
 - google analytics adapter
 - log level decreased when building docker container

juttle/juttle-engine,juttle/juttle-engine