Add metadata for current file in ContextHook

[macintacos]

Is your feature request related to a problem? Please describe.

Please see the following discussion I started in Copier for more context: https://github.com/copier-org/copier/discussions/695

Describe the solution you'd like

It would be great if we could get the current file being "worked on" before the hook method is called so that we can add some conditional logic based on the file's name.

Describe alternatives you've considered

See this comment: https://github.com/copier-org/copier/discussions/695#discussioncomment-2958646

[pawamoy]

Great! Could you open a feature request on the copier-templates-extensions repository in fact? This way I can assign myself so that I don't forget about it slightly_smiling_face

Well I definitely forgot about it anyway :joy: Sorry! I don't have a lot of time these days. If someone wants to send a PR, I'd review it :slightly_smiling_face: Shouldn't be too hard to implement.