49925e4 Remove reference to "Fedora 21". That was seven years ago.

Authored and Committed by mattdm 2 years ago
    Remove reference to "Fedora 21". That was seven years ago.
    
    See https://ask.fedoraproject.org/t/how-to-upgrade-fedora-34-to-fedora-35/17662 for an example of a user (justifiably) confused by the reference.