Fix panic in internal.Duration UnmarshalTOML

internal/internal.go

@@ -35,11 +35,14 @@ type Duration struct {
 // UnmarshalTOML parses the duration from the TOML config file
 func (d *Duration) UnmarshalTOML(b []byte) error {
 	var err error
+
 	// Parse string duration, ie, "1s"
-	d.Duration, err = time.ParseDuration(string(b[1 : len(b)-1]))
+	if uq, err := strconv.Unquote(string(b)); err == nil && len(uq) > 0 {
+		d.Duration, err = time.ParseDuration(uq)
 		if err == nil {
 			return nil
 		}
+	}
 
 	// First try parsing as integer seconds
 	sI, err := strconv.ParseInt(string(b), 10, 64)