Updated gradle cache example

[odin-delrio]

Why:

The example using gradle caches is outdated according to https://github.com/actions/cache/blob/main/examples.md#java---gradle (wich I changed with a PR recently), if copied&pasted could cause gradle builds in GH Actions to not use the cache properly (causing slower builds than needed).

What's being changed:

The example using gradle caches.

Check off the following:

• I have reviewed my changes in staging. (look for the deploy-to-heroku link in your pull request, then click View deployment)
• For content changes, I have reviewed the localization checklist
• For content changes, I have reviewed the Content style guide for GitHub Docs.

[welcome]

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[janiceilene]

@odin-delrio Thanks so much for opening a PR! I'll get this triaged for review ⚡

[lucascosti]

Thanks a lot for updating this, @odin-delrio! I'll just do a tiny update to the wording, and then merge this in 👍

[github-actions]

Thanks very much for contributing! Your pull request has been merged 🎉 You should see your changes appear on the site in approximately 24 hours.