RFR: 8098: Remove obsolete checkformatting step in GHA

[Alex Macdonald]

On Thu, 29 Jun 2023 16:16:52 GMT, Christoph Langer <clanger at openjdk.org> wrote:

> spotless is integrated into the standard JMC build workflow now. So we can skip the separate checkformatting step in GHA.
> 
> I also fixed indentation in updatecopyrightyear.sh.

Marked as reviewed by aptmac (Reviewer).

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PR Review: https://git.openjdk.org/jmc/pull/504#pullrequestreview-1515293200