OWNERS: switch 'matches' to 'matchers'
OWNERS: switch 'matches' to 'matchers'

The original OWNERS template had a mistake which used 'matches' instead
of the field supported by the Gerrit plugin 'matchers'.  Update the
OWNERS file to have the correct field.

Signed-off-by: Patrick Williams <cbb7353e6d953ef360baf960c122346276c6e320@stwcx.xyz>
Change-Id: I4fa1ff001fbd83ef87d85f2d4c41d1c973acdcb4

openbmc/btbridge,openbmc/btbridge