Update strip.go

[FIX] Deprecated io/ioutil

Author: l3dlp

strip.go

@@ -10,7 +10,7 @@ import (
 	"fmt"
 	"html"
 	"io"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"reflect"
 	"strings"
@@ -3554,7 +3554,7 @@ func parseFiles(t *Template, filenames ...string) (*Template, error) {
 		return nil, fmt.Errorf("html/template: no files named in call to ParseFiles")
 	}
 	for _, filename := range filenames {
-		b, err := ioutil.ReadFile(filename)
+		b, err := os.ReadFile(filename)
 		if err != nil {
 			return nil, err
 		}