Github actions checkout changed to pull only a single generated merge
commit instead of the actual PR commit id. This breaks check_format
test for signoff. Pulling history of 2 will include the actual commit
ID.
Change-Id: I7d83871159d24faaf2f8e6086f12173e14cbcf3c
Signed-off-by: Greg Tucker <greg.b.tucker@intel.com>