Generate __version__ at build to avoid slow importlib.metadata

[hugovk]

With Python 3.12.4:

python -X importtime -c "import pypistats" 2> import.log && tuna import.log

Cuts out the 23ms importlib.metadata import.

The call itself can also be slow, for example, 15ms in some venvs.

main

❯ hyperfine --warmup 8 "pypistats --version"
Benchmark 1: pypistats --version
  Time (mean ± σ):      57.2 ms ±   3.3 ms    [User: 44.6 ms, System: 10.9 ms]
  Range (min … max):    51.7 ms …  72.8 ms    48 runs

PR

❯ hyperfine --warmup 8 "pypistats --version"
Benchmark 1: pypistats --version
  Time (mean ± σ):      37.4 ms ±   2.7 ms    [User: 29.0 ms, System: 7.3 ms]
  Range (min … max):    34.6 ms …  55.4 ms    74 runs

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And update some config.