Offer setup-ocaml as a starter workflow

[dra27]

At present, an OCaml repository with no workflows set-up displays this on the Actions tab:

Other languages have been able to submit workflows which are then suggested by default, however new submissions are presently blocked.

Opening this issue to track @smorimoto's first attempt at actions/starter-workflows#934.

[dra27]

Note, just in passing, that Haskell and Erlang got their workflows in before new submissions were frozen last August.

[smorimoto]

I'm trying to negotiate with the GitHub manager about this now!

[smorimoto]

This is still going on here: actions/starter-workflows#1306