.travis: don't install golangci-lint
.travis: don't install golangci-lint

golanci-lint is run as part of the go-lint GitHub action and the Travis
CI build script isn't invoking any make targets requiring golangci-lint.

Signed-off-by: Tobias Klauser <059b8b880f8441509ec8a65b50b4c6ae74ebea76@cilium.io>

cilium/cilium,michi-covalent/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium,cilium/cilium,cilium/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium