refactor: move from io/ioutil to io and os package

The io/ioutil package has been deprecated as of Go 1.16, see
https://golang.org/doc/go1.16#ioutil. This commit replaces the existing
io/ioutil functions with their new definitions in io and os packages.

Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

weed/images/orientation_test.go

@@ -1,7 +1,6 @@
 package images
 
 import (
-	"io/ioutil"
 	"os"
 	"testing"
 )
@@ -9,11 +8,11 @@ import (
 func TestXYZ(t *testing.T) {
 	fname := "sample1.jpg"
 
-	dat, _ := ioutil.ReadFile(fname)
+	dat, _ := os.ReadFile(fname)
 
 	fixed_data := FixJpgOrientation(dat)
 
-	ioutil.WriteFile("fixed1.jpg", fixed_data, 0644)
+	os.WriteFile("fixed1.jpg", fixed_data, 0644)
 
 	os.Remove("fixed1.jpg")