Revert: Gradle dependency bump in "Add CI with GitHub Actions"

[domdomegg]

Reverts Gradle dependency bump in #4078

[codecov-io]

Codecov Report

Merging #4121 (ff49baa) into master (b1a691a) will decrease coverage by 0.00%.
The diff coverage is 0.00%.

@@             Coverage Diff              @@
##             master    #4121      +/-   ##
============================================
- Coverage     10.58%   10.58%   -0.01%     
  Complexity      476      476              
============================================
  Files           343      343              
  Lines         12901    12904       +3     
  Branches       1002     1002              
============================================
  Hits           1366     1366              
- Misses        11467    11470       +3     
  Partials         68       68              

Impacted Files	Coverage Δ	Complexity Δ
.../commons/contributions/ContributionController.java	0.00% <0.00%> (ø)	0.00 <0.00> (ø)

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