ci: upgrade to gcc-13 · janden/finufft@f6c4809

Command ['python', '-m', 'pip', 'wheel', '/Users/runner/work/finufft/finufft', '--wheel-dir=/private/var/folders/vy/h7r6h43j203gstfh6fj9_tyh0000gn/T/cibw-run-3b4l7tnd/cp38-macosx_x86_64/built_wheel', '--no-deps', '-v'] failed with code 1.

Process completed with exit code 1.

gcc@13 13.3.0 is already installed and up-to-date. To reinstall 13.3.0, run: brew reinstall gcc@13