Update the release notes for v0.7.0
Merge branch 'docs/relnotes-0.7.0' of dlab/hive

from pull-request 1368

* refs/heads/docs/relnotes-0.7.0:
  Update the release notes for v0.7.0

Reviewed-by: 김덕홍 <insanehong@navercorp.com>