Makefile: Don't look for tests in api/v1
Makefile: Don't look for tests in api/v1

There are no tests here, and locally it takes multiple seconds for go to
figure this out. Exclude that directory from the set of packages to
test.

Signed-off-by: Joe Stringer <16a9a54ddf4259952e3c118c763138e83693d7fd@cilium.io>

tklauser/cilium,scanf/cilium,cilium/cilium,scanf/cilium,tgraf/cilium,scanf/cilium,tklauser/cilium,michi-covalent/cilium,scanf/cilium,scanf/cilium,cilium-team/cilium,tklauser/cilium,michi-covalent/cilium,cilium/cilium,tgraf/cilium,scanf/cilium,tgraf/cilium,cilium/cilium,tklauser/cilium,michi-covalent/cilium,scanf/cilium,cilium/cilium,cilium/cilium,tgraf/cilium,michi-covalent/cilium,tgraf/cilium,cilium-team/cilium,michi-covalent/cilium,tgraf/cilium,tklauser/cilium