Gradle 8.11.1 update cleanups

[JornVernee]

Some things were missed as part of: #264

• The action to validate the gradle wrapper accidentally uses a deprecated version
• The readme was not updated.

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Progress

• Change must not contain extraneous whitespace
• Change must be properly reviewed (no review required)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jextract.git pull/272/head:pull/272
$ git checkout pull/272

Update a local copy of the PR:
$ git checkout pull/272
$ git pull https://git.openjdk.org/jextract.git pull/272/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 272

View PR using the GUI difftool:
$ git pr show -t 272

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jextract/pull/272.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

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[openjdk]

@JornVernee This change now passes all automated pre-integration checks.

After integration, the commit message for the final commit will be:

Gradle 8.11.1 update cleanups

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been no new commits pushed to the master branch. If another commit should be pushed before you perform the /integrate command, your PR will be automatically rebased. If you prefer to avoid any potential automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[mlbridge]

Webrevs

• 00: Full (04cd6b0f)