Cherry-pick 1.2.0 changelog from previous-master

[skip ci]

Author: aantron

CHANGES.md

@@ -1,3 +1,12 @@
+v1.2.0
+------
+
+- Support for standalone documentation pages (`.mld` files) (#61).
+- Display `[@@deprecated]` attributes as the `@deprecated` tag (#57).
+- Allow each component of OCaml paths to be disambiguated using the `kind-identifer` syntax (part of #61).
+- Support OCaml 4.06.
+- Fix spurious leading blank lines in verbatim text (ocaml-doc/octavius#6).
+
 v1.1.1
 -------