RFR: 8072: Bump some maven plugins and fix warnings [v3]

[Christoph Langer]

On Wed, 24 May 2023 10:06:26 GMT, Christoph Langer <clanger at openjdk.org> wrote:

>> Current maven build of JMC core shows some warnings/validation errors that can be fixed by bumping plugin versions.
>
> Christoph Langer has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Add comment about spotless

Thanks as well for the reviews.

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PR Comment: https://git.openjdk.org/jmc/pull/486#issuecomment-1561725874