Add license FAQ question

Based on #31549 (comment) and #31549 (comment), which I also link to in the answer

Author: ericphanson

README.md

@@ -212,6 +212,12 @@ Report it to the package repository.
 You can't. Package registrations are **permanent**. A version can not be overwritten in the
 registry, and code cannot be deleted.
 
+#### Can my package be registered without an [OSI approved license](https://opensource.org/licenses)?
+
+No, sorry. The registry is maintained by volunteers, and we don't have a legal team that can thoroughly review licenses. It is very easy accidentally wander into legally murky territory when combining common OSI licenses[^1] like GPL with non-OSI licenses and we don't want to subject Julia users to that hazard when installing packages registered in General. See [these](https://github.com/JuliaRegistries/General/pull/31549#issuecomment-796671872) [comments](https://github.com/JuliaRegistries/General/pull/31549#issuecomment-804196208) for more discussion.
+
+[^1]: Note that even within the world of OSI licenses, there are combinations of OSI licenses which are not legal to use together, such as GPL2 with Apache2.
+
 ## Registry maintenance
 
 The General registry is a shared resource that belongs to the entire Julia community. Therefore, we welcome comments and suggestions from everyone in the Julia community. However, all decisions regarding the General registry are ultimately up to the discretion of the registry maintainers.