Typo in gradle example

[hakanostrom]

There is a typo in the example code for creating a new project using Gradle.

[quarkus-bot]

Thanks for your pull request!

The title of your pull request does not follow our editorial rules. Could you have a look?

• title should preferably start with an uppercase character (if it makes sense!)

_{This message is automatically generated by a bot.}

[github-actions]

🙈 The PR is closed and the preview is expired.

[gsmet]

Thanks!

[gsmet]

FTR, both --extension and --extensions are supported but sure we can adjust it here.