Remove 204 response from PATCH v2 users

[api-clients-generation-pipeline]

See DataDog/datadog-api-spec#529

[jirikuncar]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[codecov]

Codecov Report

Merging #431 into master will decrease coverage by 0.31%.
The diff coverage is 48.05%.

Impacted Files	Coverage Δ	Complexity Δ
...m/datadog/api/v1/client/api/AwsIntegrationApi.java	89.10% <ø> (ø)	13.00 <0.00> (ø)
...ava/com/datadog/api/v1/client/api/MonitorsApi.java	81.00% <ø> (ø)	15.00 <0.00> (ø)
.../datadog/api/v1/client/model/APIErrorResponse.java	20.83% <ø> (ø)	3.00 <0.00> (ø)
...va/com/datadog/api/v1/client/model/AWSAccount.java	41.11% <ø> (ø)	22.00 <0.00> (ø)
...pi/v1/client/model/AWSAccountAndLambdaRequest.java	25.00% <ø> (ø)	5.00 <0.00> (ø)
.../api/v1/client/model/AWSAccountCreateResponse.java	19.04% <ø> (ø)	3.00 <0.00> (ø)
...og/api/v1/client/model/AWSAccountListResponse.java	19.23% <ø> (ø)	3.00 <0.00> (ø)
...adog/api/v1/client/model/AWSLogsAsyncResponse.java	24.24% <ø> (ø)	5.00 <0.00> (ø)
...pi/v1/client/model/AWSLogsAsyncResponseErrors.java	25.00% <ø> (ø)	5.00 <0.00> (ø)
...tadog/api/v1/client/model/AWSLogsListResponse.java	24.44% <ø> (ø)	6.00 <0.00> (ø)
... and 296 more