Enabled support for Gnome 42.

[pragmaticlinuxblog]

Hello Otto,

Really enjoying your Screenshot Tool extension!

After upgrading to Gnome 42 recently, I manually changed metadata.json to enabled support for Gnome 42. Your extension seems to work fine on it. I've been using it for over a week now. I figured I might as well create a pull request for this minor little change. Hopefully this will result in a new release of this extension on the Gnome Extensions website in the near future.

Take care,

Frank

[matthijskooijman]

I've also tested this by making the change manually on gnome 42, seems to work as expected!

[OttoAllmendinger]

thanks for testing!