domain: fast new a etcd session when the session is stale in the sche…

…maVersionSyncer (pingcap#7774)

CHANGELOGS: Add change logs for 2.1.0-rc.2 (pingcap#7705)

CHANGELOG: Add 2.0.7 change logs (pingcap#7641)

plan: fix a bug when using correlated column as index (pingcap#7357)

docs: update change-log add 2.0.6 (pingcap#7285)

CHANGELOG: Add changelog for 2.0.5 (pingcap#7005)

*: support parallel hash agg (pingcap#6658)

CHANGELOG: Add changelog for 2.0.4 (pingcap#6846)

add pull request template (pingcap#6718)

Add change logs for 2.0.x (pingcap#6725)

Add change logs for 2.0/2.0.1/2.0.2/2.0.3