Update our google-cloud-java fork to 0.20.5-alpha-GCS-RETRY-FIX

[droazen]

This brings in some additional retries for UnknownHostException and 502 errors,
and moves us from a fork in my personal github repository to the fork in
https://github.com/broadinstitute/google-cloud-java

Resolves #4888
Resolves #5094

[droazen]

@lbergelson please review. Note that this branch will fail tests until the new maven artifact is published later today. I'll re-run tests at that time.

[lbergelson]

LGTM

[codecov-io]

Codecov Report

Merging #5099 into master will increase coverage by 0.008%.
The diff coverage is 100%.

@@              Coverage Diff               @@
##             master     #5099       +/-   ##
==============================================
+ Coverage     86.48%   86.488%   +0.008%     
- Complexity    29166     29169        +3     
==============================================
  Files          1813      1813               
  Lines        135256    135256               
  Branches      15027     15027               
==============================================
+ Hits         116969    116980       +11     
+ Misses        12825     12815       -10     
+ Partials       5462      5461        -1

Impacted Files	Coverage Δ	Complexity Δ
...stitute/hellbender/cmdline/CommandLineProgram.java	85.906% <100%> (ø)	44 <0> (ø)	⬇️
...nder/utils/runtime/StreamingProcessController.java	72.249% <0%> (+0.957%)	36% <0%> (+1%)	⬆️
...e/hellbender/engine/spark/SparkContextFactory.java	73.973% <0%> (+2.74%)	11% <0%> (ø)	⬇️
...ithwaterman/SmithWatermanIntelAlignerUnitTest.java	90% <0%> (+30%)	2% <0%> (ø)	⬇️
...utils/smithwaterman/SmithWatermanIntelAligner.java	90% <0%> (+40%)	3% <0%> (+2%)	⬆️

[droazen]

Tests passed -- merging!