filter: fix timezone of --min-age/-max-age from UTC to local as documented

Before this change if the timezone was omitted in a
--min-age/--max-age time specifier then rclone defaulted to a UTC
timezone.

This is documented as using the local timezone if the time zone
specifier is omitted which is a much more useful default and this
patch corrects the implementation to agree with the documentation.

See: https://forum.rclone.org/t/problem-utc-windows-europe-1-summer-problem/29917

fs/parseduration.go

@@ -80,7 +80,7 @@ var timeFormats = []string{
 func parseDurationDates(age string, epoch time.Time) (t time.Duration, err error) {
 	var instant time.Time
 	for _, timeFormat := range timeFormats {
-		instant, err = time.Parse(timeFormat, age)
+		instant, err = time.ParseInLocation(timeFormat, age, time.Local)
 		if err == nil {
 			return epoch.Sub(instant), nil
 		}