libargp: fix README checksum
libargp: fix README checksum

mati865/MSYS2-packages,JPeterMugaas/MSYS2-packages,waterlan/MSYS2-packages,mati865/MSYS2-packages,JPeterMugaas/MSYS2-packages,JPeterMugaas/MSYS2-packages,mati865/MSYS2-packages,waterlan/MSYS2-packages,JPeterMugaas/MSYS2-packages,mati865/MSYS2-packages,waterlan/MSYS2-packages,waterlan/MSYS2-packages