Make "you didn't install yet" instructions safer.
Make "you didn't install yet" instructions safer.

Update to the current recommended composer installation instructions.
damiankloip/psysh,lvht/psysh,adetch/psysh,damiankloip/psysh,bobthecow/psysh,adetch/psysh,lvht/psysh,bobthecow/psysh,damiankloip/psysh