Merge pull request #48287 from thockin/json-iterator

Automatic merge from submit-queue

Use json-iterator instead of ugorji for JSON.

@smarterclayton @wojtek-t

Fixes #36120
xref #18762

```release-note
Switch JSON marshal/unmarshal to json-iterator library.  Performance should be close to previous with no generated code.
```

Kubernetes-commit: 6a845c67f097cd76f9d90ab3c9c5b5603c70afe4

vendor/github.com/json-iterator/go/feature_json_number.go

@@ -0,0 +1,15 @@
+package jsoniter
+
+import "encoding/json"
+
+type Number string
+
+func CastJsonNumber(val interface{}) (string, bool) {
+	switch typedVal := val.(type) {
+	case json.Number:
+		return string(typedVal), true
+	case Number:
+		return string(typedVal), true
+	}
+	return "", false
+}