Ambiguous gempsec "licenses" attribute

The current spec for Gems lead to some ambiguities in the license documentation.

The spec suggest to use "licenses" attribute for multiple licenses. https://guides.rubygems.org/specification-reference/#licenseslicenses ....yet there is nothing that says if all the licenses would apply or if this is a choice among the list of licenses. Therefore having this list of licenses is ambiguous:

• GPL-2.0
• MIT
  could either mean GPL-2.0 or MIT or GPL-2.0 and MIT and these are two very different licenses.

My suggestion would be to deprecate the "licenses" in favor of the single "license" string and allow to use SPDX license expressions in the "license" field. These are not ambiguous: GPL-2.0 and MIT is an example of such expression.

Tell me how I can help to make this happen.

I will abide by the code of conduct.

Start with the Gems specification reference linked in the issue, focusing on the license and licenses attributes and the ambiguity around multiple licenses. The issue is done when the project agrees on the intended semantics and documents an actionable specification change, including whether SPDX expressions are supported.