Upgrade mysql-connector-java version to fix possible transaction rollback failure issue

[klboke]

What's the purpose of this PR

There is a known bug in mysql-connector-java:8.0.28 that prevents transaction rollback when useLocalSessionState=true. apollo does not disallow users to set mysql link parameters, so there may be a potential problem

• This bug was fixed in mysql-connector-java:8.0.29

• Reference: https://dev.mysql.com/doc/relnotes/connector-j/8.0/en/news-8-0-29.html

• Bug mechanism reference：https://my.oschina.net/klblog/blog/5542934

[codecov-commenter]

Codecov Report

Merging #4425 (ef71351) into master (7d25d55) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #4425      +/-   ##
============================================
- Coverage     53.41%   53.39%   -0.02%     
- Complexity     2686     2687       +1     
============================================
  Files           490      490              
  Lines         15254    15254              
  Branches       1586     1586              
============================================
- Hits           8148     8145       -3     
- Misses         6548     6552       +4     
+ Partials        558      557       -1     

Impacted Files	Coverage Δ
...ework/apollo/internals/RemoteConfigRepository.java	85.27% <0.00%> (-2.46%)	⬇️
.../apollo/internals/RemoteConfigLongPollService.java	78.44% <0.00%> (+0.59%)	⬆️

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[nobodyiam]

LGTM

[shoothzj]

@nobodyiam mysql-connector-java is under GPL 2.0 license. Can we use it directly?

[klboke]

I don't know much about the protocol rules, but I see that spring-boot and skywalking also have this dependency, and they are both open source projects for the Apache protocol. So, it shouldn't be a big problem. No other questions then, I'll merge it in first