Update to support latest spec

[Sylvester Keil]

• Use .. instead of * in open L2 intervals

[Bruce D'Arcus]

Since EDTF has been since adopted as part of ISO 8601-2, would be nice to fix this now.

[Sylvester Keil]

Yes, it's about time, thanks!

This is fixed in 3.0.1

[Bruce D'Arcus]

Thanks!

For the record, I'm just going to link back to citation-style-language/schema#284.