Generate __version__ at build to avoid slow importlib.metadata import

[hugovk]

Like hugovk/tinytext#195.

With Python 3.12.4:

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

Cuts out the 22ms importlib.metadata import.

main

❯ hyperfine -w 8 "eol --version"
Benchmark 1: eol --version
  Time (mean ± σ):      55.1 ms ±   3.8 ms    [User: 43.3 ms, System: 10.4 ms]
  Range (min … max):    50.9 ms …  71.4 ms    53 runs

PR

❯ hyperfine -w 8 "eol --version"
Benchmark 1: eol --version
  Time (mean ± σ):      38.2 ms ±   1.7 ms    [User: 29.6 ms, System: 7.3 ms]
  Range (min … max):    35.3 ms …  41.9 ms    73 runs