trivial: typo fix
trivial: typo fix

While doing some mailing list moderation, I noticed this typo in the
mailing list doc.

Signed-off-by: Tim Pepper <4807564e5a18784afafcf20dbdb5591e844b9075@vmware.com>

kubernetes/community,kubernetes/community,pwittrock/community,pwittrock/community,kubernetes/community