Update readme document of 1.2.x.

[daizhenyu]

【Fix issue】#1362

[Modification content] The readme document has been modified to adapt to version 1.2.1

[Use case description] Not required

[Self-test situation] 1. Local static check passed

[Scope of influence] Not involved

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (ef00d75) 42.78% compared to head (f1ac08e) 42.78%.

Additional details and impacted files

@@            Coverage Diff            @@
##              1.2.x    #1364   +/-   ##
=========================================
  Coverage     42.78%   42.78%           
  Complexity     3298     3298           
=========================================
  Files           824      824           
  Lines         18322    18322           
  Branches       2017     2017           
=========================================
  Hits           7839     7839           
  Misses         9502     9502           
  Partials        981      981           

Flag	Coverage Δ
unittests	42.78% <ø> (ø)

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