feat: add v1beta client

[chingor13]

Add the v1beta client

The v1alpha client will be removed separately in another PR as it has never been public and does not conform to the naming convention.

[codecov]

Codecov Report

Merging #176 into master will decrease coverage by 0.98%.
The diff coverage is 75.10%.

@@             Coverage Diff              @@
##             master     #176      +/-   ##
============================================
- Coverage     76.83%   75.85%   -0.99%     
- Complexity      212      486     +274     
============================================
  Files            18       42      +24     
  Lines          1878     4348    +2470     
  Branches          6       28      +22     
============================================
+ Hits           1443     3298    +1855     
- Misses          429     1016     +587     
- Partials          6       34      +28     

Impacted Files	Coverage Δ	Complexity Δ
.../v1beta/stub/GameServerDeploymentsServiceStub.java	6.25% <6.25%> (ø)	1.00 <1.00> (?)
...ing/v1beta/stub/GameServerClustersServiceStub.java	7.14% <7.14%> (ø)	1.00 <1.00> (?)
...le/cloud/gaming/v1beta/stub/RealmsServiceStub.java	8.33% <8.33%> (ø)	1.00 <1.00> (?)
...g/v1beta/GameServerDeploymentsServiceSettings.java	10.60% <10.60%> (ø)	2.00 <2.00> (?)
...ming/v1beta/stub/GameServerConfigsServiceStub.java	11.11% <11.11%> (ø)	1.00 <1.00> (?)
...ming/v1beta/GameServerClustersServiceSettings.java	11.66% <11.66%> (ø)	2.00 <2.00> (?)
...gle/cloud/gaming/v1beta/RealmsServiceSettings.java	15.55% <15.55%> (ø)	2.00 <2.00> (?)
...aming/v1beta/GameServerConfigsServiceSettings.java	15.90% <15.90%> (ø)	2.00 <2.00> (?)
.../GrpcGameServerClustersServiceCallableFactory.java	50.00% <50.00%> (ø)	4.00 <4.00> (?)
...b/GrpcGameServerConfigsServiceCallableFactory.java	50.00% <50.00%> (ø)	4.00 <4.00> (?)
... and 38 more

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