Release/v6.40

[huanglongchao]

Motivation:

1. fix app revision not exist
2. Solve the problem that the session starts slowly after the multi-Idc feature is turned on
3. Reduce the impact of session operation and maintenance on app traffic off
4. fix Issue of high CPU usage by the meta leader

Result:

#335
#336
#339
#340

[codecov]

Codecov Report

Merging #337 (fd6589e) into master (79ffc04) will increase coverage by 0.04%.
The diff coverage is 80.00%.

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #337      +/-   ##
============================================
+ Coverage     76.56%   76.61%   +0.04%     
  Complexity       48       48              
============================================
  Files           495      495              
  Lines         18488    18506      +18     
  Branches       1802     1805       +3     
============================================
+ Hits          14155    14178      +23     
+ Misses         3522     3515       -7     
- Partials        811      813       +2     

Files	Coverage Δ
...egistry/common/model/constants/ValueConstants.java	93.61% <100.00%> (+0.28%)	⬆️
...ipay/sofa/registry/jdbc/informer/BaseInformer.java	93.63% <100.00%> (+0.17%)	⬆️
...c/repository/impl/InterfaceAppsJdbcRepository.java	83.67% <ø> (ø)
...server/meta/provide/data/NodeOperatingService.java	77.77% <85.71%> (+0.85%)	⬆️
...server/session/metadata/MetadataCacheRegistry.java	78.78% <80.00%> (+0.66%)	⬆️
...dbc/repository/impl/AppRevisionJdbcRepository.java	69.91% <75.00%> (+5.98%)	⬆️
.../java/com/alipay/sofa/registry/util/JsonUtils.java	72.22% <50.00%> (-6.35%)	⬇️

... and 9 files with indirect coverage changes

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[nocvalight]

this currentVersion may not be concurrency safe.

[huanglongchao]

Why worry about concurrency when there is no multi-value write operation?

[nocvalight]

The method queryOperateInfoAndVersion() is a public method, we cannot assume that the queryOperateInfoAndVersion() method will always be called by a single thread. If queryOperateInfoAndVersion() was called concurrency, the currentVersion will write concurrency.

[huanglongchao]

All updates currentVer from db, Concurrent writes are also not a problem, right?

[huanglongchao]

And db config is updated by Optimistic Locking with version