Update go dependencies

vendor/go.opencensus.io/stats/internal/validation.go

@@ -1,28 +0,0 @@
-// Copyright 2018, OpenCensus Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package internal // import "go.opencensus.io/stats/internal"
-
-const (
-	MaxNameLength = 255
-)
-
-func IsPrintable(str string) bool {
-	for _, r := range str {
-		if !(r >= ' ' && r <= '~') {
-			return false
-		}
-	}
-	return true
-}