Downgrade Kubernetes vendor version

Multus community decide that multus support the Kubernetes that
Kubernetes community supports, so changed vendor code to the
oldest version of currently supported.

vendor/github.com/google/go-cmp/cmp/internal/value/zero.go

@@ -1,48 +0,0 @@
-// Copyright 2017, The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE.md file.
-
-package value
-
-import (
-	"math"
-	"reflect"
-)
-
-// IsZero reports whether v is the zero value.
-// This does not rely on Interface and so can be used on unexported fields.
-func IsZero(v reflect.Value) bool {
-	switch v.Kind() {
-	case reflect.Bool:
-		return v.Bool() == false
-	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-		return v.Int() == 0
-	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
-		return v.Uint() == 0
-	case reflect.Float32, reflect.Float64:
-		return math.Float64bits(v.Float()) == 0
-	case reflect.Complex64, reflect.Complex128:
-		return math.Float64bits(real(v.Complex())) == 0 && math.Float64bits(imag(v.Complex())) == 0
-	case reflect.String:
-		return v.String() == ""
-	case reflect.UnsafePointer:
-		return v.Pointer() == 0
-	case reflect.Chan, reflect.Func, reflect.Interface, reflect.Ptr, reflect.Map, reflect.Slice:
-		return v.IsNil()
-	case reflect.Array:
-		for i := 0; i < v.Len(); i++ {
-			if !IsZero(v.Index(i)) {
-				return false
-			}
-		}
-		return true
-	case reflect.Struct:
-		for i := 0; i < v.NumField(); i++ {
-			if !IsZero(v.Field(i)) {
-				return false
-			}
-		}
-		return true
-	}
-	return false
-}