guess_license_from_pod does not recognize license version in parens

In my module's license section, there is the following text (which was inserted by module-starter):

```
This program is free software; you can redistribute it and/or modify it
under the terms of the the Artistic License (2.0).
```

But, the list returned by guess_license_from_pod was:

```
Software::License::Artistic_1_0 Software::License::Artistic_2_0
```
