Update dependencies (#302)

go.mod

@@ -1,16 +1,16 @@
 module github.com/Shopify/kubeaudit
 
 require (
-	github.com/jetstack/cert-manager v0.15.0
+	github.com/jetstack/cert-manager v1.0.1
 	github.com/sirupsen/logrus v1.6.0
 	github.com/spf13/cobra v1.0.0
-	github.com/stretchr/testify v1.5.1
+	github.com/stretchr/testify v1.6.1
 	gopkg.in/yaml.v1 v1.0.0-20140924161607-9f9df34309c0
-	gopkg.in/yaml.v3 v3.0.0-20200506231410-2ff61e1afc86
-	k8s.io/api v0.18.3
-	k8s.io/apiextensions-apiserver v0.18.3
-	k8s.io/apimachinery v0.18.3
-	k8s.io/client-go v0.18.3
+	gopkg.in/yaml.v3 v3.0.0-20200615113413-eeeca48fe776
+	k8s.io/api v0.19.1
+	k8s.io/apiextensions-apiserver v0.19.1
+	k8s.io/apimachinery v0.19.1
+	k8s.io/client-go v0.19.1
 )
 
 go 1.13