fix: mark package as typed

[sisp]

I've added the file py.typed to mark the copier package as typed when imported in other projects.

Fixes #1381.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (cc1ca14) 97.36% compared to head (75ec513) 97.36%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1431   +/-   ##
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  Coverage   97.36%   97.36%           
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  Files          48       48           
  Lines        4520     4520           
=======================================
  Hits         4401     4401           
  Misses        119      119           

Flag	Coverage Δ
unittests	97.36% <ø> (ø)

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[sisp]

Or would the change type build(typing) be better? 🤔 It wouldn't appear in the changelog though ...

[bswck]

Not strictly related to the PR: This project needs some modernization of type hints (don't use typing.Union, typing.Callable, etc.), a bit like here CERT-Polska/malduck#111 (I am mainly thinking of CERT-Polska/malduck@197dca8).

I would wait with merging this PR as long as the codebase does not fully pass mypy --strict, which I can confirm without checking at the moment, for example because of some non-parametrized generics (Mapping, Path, etc.).

I am aware of that pydantic renders type annotations at runtime. I am aware that the earliest supported Python version is 3.8.
I can devote some time for this. Do you mind me opening an issue to modernize type hinting in the project @yajo?

[yajo]

@bswck of course you're welcome to help improving type hints! You could even add the strict mode to our mypy checks, so we make sure there are no regressions on that.

OTOH, I see no reason for blocking this PR to wait for your improvement.