Recommend the usage of SPDX license identifiers in the license field

[Calinou]

The specification currently states:

license

An OSI license name or an URL to a license file (String, recommended).

It could be a good idea to rely on SPDX license identifiers for common licenses out there, which would make it easier to parse license fields programmatically. This is encouraged by many other package managers already, such as Cargo.

[ysbaddaden]

The SPEC should specify a license identifier instead of name, because this is what we expect, and add some examples, such as Apache-2.0, MIT, BSD-3-clause, ... OSI and SPDX use the same identifiers , so that doesn't really matter and could link to both.

[RX14]

@ysbaddaden the SPDX URL makes it easier to find the indentifier for a licence, since it's all on one page.

[ysbaddaden]

Same for OSI: https://opensource.org/licenses/alphabetical expect that it's not just a list of opensource licenses. We can reference the blunt SPDX table, but I'd still like to keep referencing OSI, for example the https://opensource.org/licenses/category page, which is nicer.

[RX14]

@ysbaddaden yeah that page is nice! I didn't see an OSI page like that before

[ysbaddaden]

I'm not sure how to phrase the SPEC, thought.

[bcardiff]

Removing this from milestone 0.10.0. When there is a PR this can be milestoned again.

[straight-shoota]

Resolved by #641