edac: Increase version to 3.0.0

There were lots of changes introduced to justify renaming it to
3.0.0:

  - EDAC core were redesigned to represent all types of
    memory controllers;

  - EDAC API were redesigned to properly represent the memory
    controller hierarchy;

  - a tracepoint-based API were added to report memory errors.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>