upgrade spring-boot to 2.4.2 and spring-cloud to 2020.0.1

[nobodyiam]

What's the purpose of this PR

upgrade spring-boot and spring-cloud to latest releases

Which issue(s) this PR fixes:

Fixes #3485 #3504

Brief changelog

upgrade spring-boot to 2.4.2 and spring-cloud to 2020.0.1

Follow this checklist to help us incorporate your contribution quickly and easily:

• Read the Contributing Guide before making this pull request.
• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• Write necessary unit tests to verify the code.
• Run mvn clean test to make sure this pull request doesn't break anything.

[codecov-io]

Codecov Report

Merging #3507 (fe4f06c) into master (41519f4) will decrease coverage by 0.05%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #3507      +/-   ##
============================================
- Coverage     51.44%   51.39%   -0.06%     
+ Complexity     2320     2318       -2     
============================================
  Files           442      442              
  Lines         13843    13843              
  Branches       1408     1408              
============================================
- Hits           7121     7114       -7     
- Misses         6230     6239       +9     
+ Partials        492      490       -2     

Impacted Files	Coverage Δ	Complexity Δ
...mework/apollo/portal/component/PortalSettings.java	57.81% <0.00%> (-7.82%)	5.00% <0.00%> (ø%)
...framework/apollo/openapi/entity/ConsumerAudit.java	42.42% <0.00%> (-6.07%)	9.00% <0.00%> (-2.00%)
...mework/apollo/openapi/service/ConsumerService.java	47.57% <0.00%> (-1.95%)	12.00% <0.00%> (-1.00%)
.../apollo/internals/RemoteConfigLongPollService.java	78.31% <0.00%> (+1.20%)	29.00% <0.00%> (+1.00%)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f817182...fe4f06c. Read the comment docs.