README: Update mail address

linux-yocto@yoctoproject.org bounces with a:
I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

Update the email address to the new one to correct the issue.

Signed-off-by: Jon Mason <jdmason@kudzu.us>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>