feat: expose hivepartitioningoptions

[pmakani]

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Towards #202

[codecov]

Codecov Report

Merging #233 into master will decrease coverage by 0.00%.
The diff coverage is 77.27%.

@@             Coverage Diff              @@
##             master     #233      +/-   ##
============================================
- Coverage     77.36%   77.35%   -0.01%     
- Complexity     1116     1125       +9     
============================================
  Files            73       74       +1     
  Lines          5950     5993      +43     
  Branches        626      630       +4     
============================================
+ Hits           4603     4636      +33     
- Misses         1019     1025       +6     
- Partials        328      332       +4     

Impacted Files	Coverage Δ	Complexity Δ
...om/google/cloud/bigquery/LoadJobConfiguration.java	87.02% <33.33%> (-2.62%)	52.00 <0.00> (ø)
...google/cloud/bigquery/HivePartitioningOptions.java	93.75% <93.75%> (ø)	9.00 <9.00> (?)

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