Port to OCaml 5.0.0, bump version to 1.3. * minor fixup for camlp5 8.00 there are now PPX attributes in many places, so (for example) what was a pair (pattern * expression) is now a triple (pattern * expression * attributes). Typically the attributes are empty in generated code. Since this is a spot that can have a meta-variable in quotations, we have to wrap the empty-list in a "vala". But again, this is pretty much a boilerplate value. Co-authored-by: Chet Murthy <chetsky@gmail.com>