Set FsGroup for spring boot test

[feloy]

What type of PR is this:
/area testing

What does this PR do / why we need it:

This PR fixes the following Kubernetes-Docs-Integration-Tests test, by setting an fsGroup to the container's pod.

 [FAILED] user-guides/quickstart/docs-mdx/java/java_odo_dev_output.mdx
  Expected
      <string>:   (
        	"""
        	... // 12 identical lines
        	✓  Pod is Running
        	✓  Syncing files into the container [1s]
      - 	✓  Building your application in container (command: build) [1s]
      - 	•  Executing the application (command: run)  ...
      - 	✓  Waiting for the application to be ready [1s]
      - 	-  Forwarding from 127.0.0.1:20001 -> 8080
      + 	✗  Building your application in container (command: build) [1s]
      + 	Error occurred on Push - watch command was unable to push component: unable to exec command [/bin/sh -c cd ${PROJECT_SOURCE} && (mvn clean -Dmaven.repo.local=/home/user/.m2/repository package -Dmaven.test.skip=true) 1>>/proc/1/fd/1 2>>/proc/1/fd/2]: error while streaming command: command terminated with exit code 1
        	
        	
        	... // 9 identical lines
        	"""
        )

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[rm3l]

Thanks!