Pin odoc-parser version to less than 2.3.0

Author: tmcgilchrist

odoc.opam

@@ -25,7 +25,7 @@ delimited with `(** ... *)`, and outputs HTML.
 """
 
 depends: [
-  "odoc-parser" {>= "2.0.0"}
+  "odoc-parser" {>= "2.0.0" & < "2.3.0"}
   "astring"
   "cmdliner" {>= "1.0.0"}
   "cppo" {build & >= "1.1.0"}