Improve performance

[hexaron]

Making a subprocess call on every directory is not acceptable.

gitkeep/gitkeep

Lines 172 to 179 in bb2290d

	subprocess.check_output(
	(
	f"find {d.relative_to(Path.cwd())} -maxdepth 1 -type d"
	f" | git check-ignore --stdin"
	),
	shell=True,
	stderr=subprocess.STDOUT # Do not print errors in console
	)

[hexaron]

Profiling revealed the following stats:

         23315 function calls (23227 primitive calls) in 0.563 seconds

   Ordered by: cumulative time

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
       74    0.001    0.000    0.522    0.007 /usr/lib/python3.10/subprocess.py:373(check_output)
       74    0.002    0.000    0.521    0.007 /usr/lib/python3.10/subprocess.py:460(run)
       74    0.001    0.000    0.479    0.006 /usr/lib/python3.10/subprocess.py:1105(communicate)
       92    0.469    0.005    0.469    0.005 {method 'read' of '_io.BufferedReader' objects}
       74    0.002    0.000    0.040    0.001 /usr/lib/python3.10/subprocess.py:753(__init__)
       74    0.003    0.000    0.035    0.000 /usr/lib/python3.10/subprocess.py:1682(_execute_child)
       74    0.024    0.000    0.024    0.000 {built-in method _posixsubprocess.fork_exec}
     19/2    0.000    0.000    0.012    0.006 <frozen importlib._bootstrap>:1022(_find_and_load)
     19/2    0.000    0.000    0.012    0.006 <frozen importlib._bootstrap>:987(_find_and_load_unlocked)
     14/2    0.000    0.000    0.012    0.006 <frozen importlib._bootstrap>:664(_load_unlocked)
      9/2    0.000    0.000    0.011    0.006 <frozen importlib._bootstrap_external>:877(exec_module)
       74    0.000    0.000    0.011    0.000 /home/jacob/bin/gitkeep:211(<listcomp>)
     20/2    0.000    0.000    0.011    0.005 <frozen importlib._bootstrap>:233(_call_with_frames_removed)
      9/2    0.000    0.000    0.011    0.005 {built-in method builtins.exec}
      427    0.001    0.000    0.008    0.000 /usr/lib/python3.10/pathlib.py:1011(iterdir)
...