JHipster 8.9.0 release notes have wrong date in URL

[mraible]

I made a mistake in the 8.9.0 release process and didn't update the slug at the top of the release notes file:

slug: /2024/12/23/jhipster-release-8.9.0.html

Since I've already promoted the release on social media, I think the best way to fix this is to 1) update the slug and 2) add a redirect from the old URL.

@SvMak Do you know how to do this with Docusaurus?