nghttpx-ingress-lb v0.40.0

• Add redirectIfNotTLS path-config (GH-119)
• Get rid of k8s.io/kubernetes dependency because it is not reusable (GH-115)
• Verify that TLS private key matches public key (GH-114)
• Upgrade go.mod based on k8s v1.15.0 (GH-113)