config/git: use flashprog instead of flashrom
    
    Nico Huber is the rightful project lead. I do not support
    the coup that occured within the flashrom project. Nico
    has always been of great service to the Libreboot project,
    by virtue of his work on both coreboot and flashrom.
    
    Nico Huber was unfairly removed from the flashrom project
    infrastructure, due to unfounded accusations hurled at him
    by flashrom's new project lead. The accusations are unfounded
    because no evidence was given.
    
    Use Nico Huber's fork, named flashprog. We will work with
    flashprog from now on.
    
    Signed-off-by: Leah Rowe <leah@libreboot.org>