Updating yojson to 2.0.2

[julien.puydt@gmail.com]

Hi,

the yojson package was RFA ; I just took it over and uploaded version
2.0.2 to experimental.

I know it breaks the following packages:

- ocaml-atd 2.9.1 -- but 2.10.0 works (uploaded to experimental) 

- belenios through ocaml-atd -- and rebuilding against 2.10.0 doesn't
work, I need to look into it.

- morbig -- I could patch it easily (uploaded to experimental)

- zeroinstall-injector -- not managed within the Debian OCaml
maintainers, so I can't do much ; Thomas in CC is responsible, and I
have a patch, see below.

I know it doesn't break:

- frama-c
- js-of-ocaml
- liquidsoap
- ppx-deriving-yojson

and I think that's a complete picture.

Cheers,

J.Puydt

PS: for zeroinstall-injector, the patch is:

Description: fix support for yojson 2.0.2
Author: Julien Puydt
Forwarded: https://github.com/0install/0install/issues/195

--- zeroinstall-injector-2.16.orig/src/support/json.ml
+++ zeroinstall-injector-2.16/src/support/json.ml
@@ -1,3 +1,3 @@
 [@@@ocaml.warning "-3"]
 
-type t = Yojson.Basic.json
+type t = Yojson.Basic.t
--- zeroinstall-injector-2.16.orig/0install.opam
+++ zeroinstall-injector-2.16/0install.opam
@@ -11,7 +11,7 @@
 ]
 depends: [
   "ocaml" {>= "4.05.0"}
-  "yojson"
+  "yojson" {>= "2.0.2"}
   "xmlm"
   "ounit" {with-test}
   "lwt"