Bump sigs.k8s.io/controller-runtime in /operator-apis

Bumps [sigs.k8s.io/controller-runtime](https://github.com/kubernetes-sigs/controller-runtime) from 0.6.3 to 0.8.1.
- [Release notes](https://github.com/kubernetes-sigs/controller-runtime/releases)
- [Commits](kubernetes-sigs/controller-runtime@v0.6.3...v0.8.1)

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

operator-apis/go.mod

@@ -4,14 +4,14 @@ go 1.15
 
 require (
 	github.com/cloudfoundry-incubator/service-fabrik-broker/interoperator v0.0.0-00010101000000-000000000000
-	github.com/go-logr/logr v0.1.0
+	github.com/go-logr/logr v0.3.0
 	github.com/gorilla/mux v1.8.0
 	github.com/onsi/ginkgo v1.14.2
 	github.com/onsi/gomega v1.10.3
-	k8s.io/api v0.18.8
-	k8s.io/apimachinery v0.18.8
-	k8s.io/client-go v0.18.8
-	sigs.k8s.io/controller-runtime v0.6.3
+	k8s.io/api v0.20.2
+	k8s.io/apimachinery v0.20.2
+	k8s.io/client-go v0.20.2
+	sigs.k8s.io/controller-runtime v0.8.1
 )
 
 replace github.com/cloudfoundry-incubator/service-fabrik-broker/interoperator => ../interoperator