Unhandled EventAlertType "user_update"

[ni3mm4nd]

Describe the bug
If event contains "alert_type":"user_update" an exception is raised.

To Reproduce
Steps to reproduce the behavior:

1. fetch events from datadog
2. try to parse it
3. an exception occured
4. See error

Caused by: com.fasterxml.jackson.databind.exc.ValueInstantiationException: Cannot construct instance of 'com.datadog.api.v1.client.model.EventAlertType', problem: Unexpected value 'user_update'

Expected behavior
All possible alert types should be covered in EventAlertType enum class

Environment and Versions (please complete the following information):
`

	<dependency>
		<groupId>com.datadoghq</groupId>
		<artifactId>datadog-api-client</artifactId>
		<version>1.0.0-beta.6</version>
	</dependency>`

Example of fetched events
{ "events": [ { "alert_type": "user_update", "comments": [], "date_happened": 1603179512, ...

[github-actions]

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