Bump OCaml version upper-bound

dune-project

@@ -15,7 +15,7 @@
  (name clangml-transforms)
  (synopsis "Code transformers for clangml")
  (depends
-  (ocaml (and (>= 4.03.0) (< 4.11.0)))
+  (ocaml (and (>= 4.03.0) (< 4.12.0)))
   (dune (>= 2.2.0))
   (clangml (>= 4.1.0))
   (dolog (>= 4.0.0))