Add Reason upper bound for 0.12

[anmonteiro]

• needs to have an upper bound < 3.10
• patch 0.11 in opam with the same upper bound
• make reactjs-jsx-ppx incompatible with reason-react >= 0.12
• maybe use post-messages (like merlin)

[jchavarri]

patch 0.11 in opam with the same upper bound

Second item is being added in ocaml/opam-repository#24367.

[davesnx]

• 1 and 2 are done. reason-react 0.11 and 0.12 have this {>= "3.6.0" & < "3.10.0"}

Would you add a conflict on reactjs-jsx-ppx?

[anmonteiro]

• 1 and 2 are done. reason-react 0.11 and 0.12 have this {>= "3.6.0" & < "3.10.0"}

Would you add a conflict on reactjs-jsx-ppx?

I think it should be fine, actually. People depend only on reason-react, which brings the ppx along as a a dependency. We don't expect this reactjs-jsx-ppx name to end up in their dependencies.

[davesnx]

I we don't mention reactjs-jsx-ppx I don't think people will face the issue also