Bump k8s.io/apiserver from 0.0.0-20190805142138-368b2058237c to 0.15.10

Bumps [k8s.io/apiserver](https://github.com/kubernetes/apiserver) from 0.0.0-20190805142138-368b2058237c to 0.15.10.
- [Commits](https://github.com/kubernetes/apiserver/commits/v0.15.10)

---
updated-dependencies:
- dependency-name: k8s.io/apiserver
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

go.mod

@@ -21,9 +21,9 @@ require (
 	github.com/virtual-kubelet/virtual-kubelet v0.10.0
 	go.opencensus.io v0.21.0
 	gopkg.in/inf.v0 v0.9.1 // indirect
-	k8s.io/api v0.0.0
-	k8s.io/apimachinery v0.0.0
-	k8s.io/apiserver v0.0.0-20190805142138-368b2058237c // indirect
+	k8s.io/api v0.15.10
+	k8s.io/apimachinery v0.15.10
+	k8s.io/apiserver v0.15.10 // indirect
 	k8s.io/client-go v11.0.0+incompatible
 	k8s.io/klog v0.3.3
 	k8s.io/kubernetes v1.14.3 // indirect