Upgrade k8s.io/client-go to kubernetes-1.9.1

Upgraded from 99c19923, branch release-3.0.

This required fetching or upgrading the following:
* k8s.io/api to kubernetes-1.9.1
* k8s.io/apimachinery to kubernetes-1.9.1
* github.com/juju/ratelimit to 1.0.1
* github.com/spf13/pflag to 4c012f6d

Also, update Scope's imports/function calls to be compatible with the new client.

vendor/github.com/json-iterator/go/skip_tests/string/inputs.go

@@ -0,0 +1,14 @@
+package test
+
+type typeForTest string
+
+var inputs = []string{
+	`""`,       // valid
+	`"hello"`,  // valid
+	`"`,        // invalid
+	`"\"`,      // invalid
+	`"\x00"`,   // invalid
+	"\"\x00\"", // invalid
+	"\"\t\"",   // invalid
+	`"\t"`,     // valid
+}