drop support for Coq 8.13
This should let us re-land !756 (merged). :)
Also document that we generally aim to supported the two most recent stable Coq releases, which has been our de-facto policy for a while.
This should let us re-land !756 (merged). :)
Also document that we generally aim to supported the two most recent stable Coq releases, which has been our de-facto policy for a while.