[new release] redirect.0.2.1
[new release] redirect.0.2.1

This PR adds the new release for redirect.0.2.1:

- Fix `with_channel_from_string` for long strings that do not fit in
  pipe, by using a thread for outputing the string.

- Some minor optimizations, using the fact that re-raising an exception
  preserves the backtrace and the constraint on OCaml version (>=4.03)
  ensures that match-with-exception is available.

emillon/opam-repository,ocaml/opam-repository,andersfugmann/opam-repository,hannesm/opam-repository,jhwoodyatt/opam-repository,jhwoodyatt/opam-repository,toots/opam-repository,hannesm/opam-repository,Leonidas-from-XIV/opam-repository,codinuum/opam-repository,pqwy/opam-repository,kkirstein/opam-repository,Chris00/opam-repository,codinuum/opam-repository,yallop/opam-repository,Chris00/opam-repository,nberth/opam-repository,pirbo/opam-repository,astrada/opam-repository,pirbo/opam-repository,c-cube/opam-repository,mjambon/opam-repository,pqwy/opam-repository,djs55/opam-repository,fpottier/opam-repository,mjambon/opam-repository,yallop/opam-repository,c-cube/opam-repository,nberth/opam-repository,emillon/opam-repository,kkirstein/opam-repository,fpottier/opam-repository,astrada/opam-repository,toots/opam-repository,djs55/opam-repository,andersfugmann/opam-repository,ocaml/opam-repository,Leonidas-from-XIV/opam-repository