Fix documentation referring to deprecated tostring method · pytroll/aggdraw@944ba80

Command ['python', '-m', 'pip', 'wheel', '/Users/runner/work/aggdraw/aggdraw', '--wheel-dir=/private/var/folders/py/lcjn3y352g1106vf1rqk521r0000gn/T/cibw-run-16pn__ea/cp39-macosx_arm64/built_wheel', '--no-deps'] failed with code 1. None

Process completed with exit code 1.

pipx 1.7.1 is already installed and up-to-date. To reinstall 1.7.1, run: brew reinstall pipx