chore(ci): Retain logs if CI (GitHub Action) build fails [gax-java]

[miraleung]

Closes #1311.

[codecov]

Codecov Report

Merging #1312 (d4cc29f) into master (bae5eb6) will decrease coverage by 0.03%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #1312      +/-   ##
============================================
- Coverage     79.69%   79.65%   -0.04%     
+ Complexity     1249     1248       -1     
============================================
  Files           209      209              
  Lines          5461     5461              
  Branches        464      464              
============================================
- Hits           4352     4350       -2     
- Misses          927      928       +1     
- Partials        182      183       +1     

Impacted Files	Coverage Δ	Complexity Δ
.../java/com/google/api/gax/batching/BatcherImpl.java	94.94% <0.00%> (-1.13%)	22.00% <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 bae5eb6...8e4dd9e. Read the comment docs.