Copyright statement with a year range ending in the word "NOW" not detected at all

### Description

A copyright statement like

```
Copyright (c) 2013-NOW Jinzhu
```

is not detected at all. If the "-NOW" part is removed from the year range, the copyright is detected.

### How To Reproduce

Run

```shell
LC_ALL=en_US.UTF-8 scancode --copyright --json-pp - LICENSE
```

on https://github.com/jinzhu/configor/blob/f7a0fc7c9fc697269b1749c1cc472d49baa8d33c/LICENSE#L3.

### System configuration

* What OS are you running on? Fedora Linux
* What version of scancode-toolkit was used to generate the scan file? 32.5.0
* What installation method was used to install/run scancode? RPM