Release Note 2.0.2.1

[xiaokang]

Previous Release Note 2.0.2

This is a BUG FIX version based on Doris 2.0.2, which contains 8 additional commits:

[1] #25968
[2] #26070
[3] #26122
Fix the problem that when rollback from future version like 2.0.3, FE can not start due to metadata not compatible.

[4] #25940
Fix the problem that user can not run DELETE WHERE on a DATEV1 column.
eg. DELETE FROM tbl WHERE col_datav1 = '2023-10-30 00:00:00'.

[5] #25717
Fix regexp_extract_all function wrong result when input is empty str.

[6] #25955
[7] #26034
Fix the problem 'Subquery is not supported in the select list' in new optimizer.

[8] #26136
Fix the problem that MySQL load create too many threads.

Thanks all who contribute to this release:
@Gabriel39
@morningman
@zhangstar333
@starocean999
@Kikyou1997
@CalvinKirs