epy: add python3-magic as dependency

[yushisora]

It is mentioned in #54741 that a patch is added in b21778d to replace imghdr with magic but then python3-magic is missing from epy dependency.

Testing the changes

• I tested the changes in this PR: briefly

Local build testing

• I built this PR locally for my native architecture, (aarch64-glibc)

[yushisora]

PYTHON: py3:magic <-> UNKNOWN PKG PLEASE FIX!

Any tips on how to fix it?

[classabbyamp]

the patch should be adjusted to add a dependency on python-magic (what we package as python3-magic), as that's a different thing than magic

[Rutpiv]

Replacing +magic = { version = "*" } with +python-magic = { version = "*" } in no-imghdr.patch is enough to resolve the issue. The functions used are compatible, and after testing, image detection works as expected.

I also noticed that python3-magic in Void was outdated, so I updated the template accordingly. The corresponding PR is here: #58336

[yushisora]

Thanks. Already changed the patch as suggested.