Bump Maven from 3.8.7 to 3.9.4

[valfirst]

No description provided.

[codecov-commenter]

Codecov Report

Merging #196 (fff4587) into master (fb57013) will decrease coverage by 63.04%.
The diff coverage is n/a.

❗ Current head fff4587 differs from pull request most recent head bc55b82. Consider uploading reports for the commit bc55b82 to get more accurate results

@@             Coverage Diff              @@
##             master    #196       +/-   ##
============================================
- Coverage     63.03%   0.00%   -63.04%     
============================================
  Files            12      12               
  Lines          1028    1028               
  Branches        149     149               
============================================
- Hits            648       0      -648     
- Misses          325    1028      +703     
+ Partials         55       0       -55     

see 10 files with indirect coverage changes

[diemol]

Thank you, @valfirst!