Remove myself from codeowners of client/**

Signed-off-by: Daniel Nephin <dnephin@gmail.com>

.github/CODEOWNERS

@@ -4,7 +4,6 @@
 # KEEP THIS FILE SORTED. Order is important. Last match takes precedence.
 
 builder/**                              @tonistiigi
-client/**                               @dnephin
 contrib/mkimage/**                      @tianon
 daemon/graphdriver/devmapper/**         @rhvgoyal 
 daemon/graphdriver/lcow/**              @johnstep @jhowardmsft