docs: add a version notice in the Open API documentation

[mghio]

What's the purpose of this PR

add a version notice in the Open API(zh docs, en docs) documentation.

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• Update the CHANGES log.

[codecov-commenter]

Codecov Report

Merging #4585 (4c408aa) into master (3436df8) will increase coverage by 0.03%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #4585      +/-   ##
============================================
+ Coverage     53.44%   53.48%   +0.03%     
- Complexity     2725     2727       +2     
============================================
  Files           495      495              
  Lines         15460    15460              
  Branches       1599     1599              
============================================
+ Hits           8263     8269       +6     
+ Misses         6631     6627       -4     
+ Partials        566      564       -2     

Impacted Files	Coverage Δ
...ervice/service/ReleaseMessageServiceWithCache.java	87.05% <0.00%> (+1.17%)	⬆️
...ework/apollo/internals/RemoteConfigRepository.java	88.34% <0.00%> (+3.06%)	⬆️

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[nobodyiam]

LGTM