Migrate Junit4 to Junit Vintage and replace deprecated methods

[linghengqian]

For #2258.

Changes proposed in this pull request:

• Migrate Junit4 to Junit Vintage and replace deprecated methods.
• Update maven-surefire-plugin to 3.1.2 to solve the problem of Warning reported by Junit Platform related classes in the unit test of Spring Boot Starter and Spring Namespace.
• Update mockito to the last version that supports JDK8.

[codecov-commenter]

Codecov Report

Merging #2259 (4668bee) into master (5e466de) will decrease coverage by 0.04%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #2259      +/-   ##
============================================
- Coverage     84.43%   84.40%   -0.04%     
- Complexity     1926     1927       +1     
============================================
  Files           287      287              
  Lines          6341     6341              
  Branches        704      704              
============================================
- Hits           5354     5352       -2     
  Misses          662      662              
- Partials        325      327       +2     

see 2 files with indirect coverage changes

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