chore: release gapic-generator-java v0.0.21 with gapic_metadata.json support

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PiperOrigin-RevId: 358516065
Source-Link: googleapis/googleapis@af8f71d

[codecov]

Codecov Report

Merging #432 (9f5f62b) into master (19e2d6d) will increase coverage by 9.59%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master     #432      +/-   ##
============================================
+ Coverage     72.63%   82.23%   +9.59%     
- Complexity      496      595      +99     
============================================
  Files            24       24              
  Lines          2383     3906    +1523     
  Branches         10       48      +38     
============================================
+ Hits           1731     3212    +1481     
- Misses          586      610      +24     
- Partials         66       84      +18     

Impacted Files	Coverage Δ	Complexity Δ
...v1beta1/PolicyTagManagerSerializationSettings.java	21.21% <0.00%> (-2.13%)	2.00% <0.00%> (ø%)
.../datacatalog/v1beta1/PolicyTagManagerSettings.java	13.20% <0.00%> (-0.26%)	2.00% <0.00%> (ø%)
...ogle/cloud/datacatalog/v1/DataCatalogSettings.java	8.64% <0.00%> (-0.11%)	2.00% <0.00%> (ø%)
...cloud/datacatalog/v1beta1/DataCatalogSettings.java	8.64% <0.00%> (-0.11%)	2.00% <0.00%> (ø%)
...ud/datacatalog/v1beta1/PolicyTagManagerClient.java	79.05% <0.00%> (+1.18%)	59.00% <0.00%> (+12.00%)
...g/v1beta1/PolicyTagManagerSerializationClient.java	44.44% <0.00%> (+2.13%)	7.00% <0.00%> (ø%)
...cloud/datacatalog/v1/stub/GrpcDataCatalogStub.java	97.79% <0.00%> (+2.87%)	34.00% <0.00%> (+1.00%)
.../datacatalog/v1beta1/stub/GrpcDataCatalogStub.java	97.79% <0.00%> (+2.87%)	34.00% <0.00%> (+1.00%)
...tub/PolicyTagManagerSerializationStubSettings.java	75.00% <0.00%> (+3.07%)	11.00% <0.00%> (ø%)
...google/cloud/datacatalog/v1/DataCatalogClient.java	86.59% <0.00%> (+3.83%)	150.00% <0.00%> (+40.00%)
... and 6 more

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