Update email address and mailing list for v9fs

Update email address and mailing list for v9fs

We've recently moved the mailing list to lists.linux.dev to move away
from the sourceforge infrastructure.  This also updates the website
from the (no longer v9fs relevant?) swik.net address to the github
group which contains pointers to test cases, the protocol, servers,
etc.  This also changes my email from my gmail to my kernel.org
address.

Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
Acked-by: Dominique Martinet <asmadeus@codewreck.org>
Acked-by: Christian Schoenebeck <linux_oss@crudebyte.com>