Release v1.5.3

[csuzhangxc]

This is an issue tracking the tidb-operator v1.5.3 release.

Previous:

• 5509

Pending PRs:

TODO:

• [x] Update default version of TiDB Operator #5620
• [x] Update TiDB version and tools version if necessary #5620
• [x] Update the TiDB version and tools version in docs-tidb-operator repo https://github.com/pingcap/docs-tidb-operator/pull/2556
• [x] Update release notes https://github.com/pingcap/docs-tidb-operator/pull/2557
• [x] Update Github Releases
• [x] Build and publish docker images/helm charts
• [x] Announcement (slack, email, etc.)
• [x] Update TiDB Operator version in docs-tidb-operator repo (both for dev and stable branch) https://github.com/pingcap/docs-tidb-operator/pull/2558