Restrict apimachinery dependency to v0.17.2

A mismatch between the apimachinery and client-go versions results in a

errConfigurationInvalid does not implement "k8s.io/apimachinery/pkg/util/errors".Aggregate (missing Is method)

build error. Restrict the API level until the other dependencies have had
a chance to catch up.

Author: pmundt

go.mod

@@ -1,11 +1,11 @@
 module k8s-dt-node-labeller
 
-go 1.14
+go 1.13
 
 require (
 	github.com/go-logr/logr v0.1.0
 	github.com/platinasystems/fdt v1.0.1
-	k8s.io/api v0.18.0
-	k8s.io/apimachinery v0.18.0
+	k8s.io/api v0.17.2
+	k8s.io/apimachinery v0.17.2
 	sigs.k8s.io/controller-runtime v0.5.2
 )