chore: enable lint (fmt-maven-plugin and checkstyle)

[meltsufin]

No description provided.

[suztomo]

There must be some unnecessary command basename. The checkstyle Maven invocation succeeded.

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  38.084 s
[INFO] Finished at: 2022-10-14T14:52:49Z
[INFO] ------------------------------------------------------------------------
basename: missing operand
Try 'basename --help' for more information.

[suztomo]

basename command here https://github.com/googleapis/google-cloud-java/blob/main/.kokoro/coerce_logs.sh#L26 This script is called in https://github.com/googleapis/google-cloud-java/blob/main/.kokoro/build.sh#L145 (after checkstyle is done)

[meltsufin]

@suztomo Apparently build.sh in the current form doesn't work on GitHub actions, although it works in other repos.

[suztomo]

Do not merge to main until the release goes through. (updating main branch resets the release pull request)