docs(CHANGES): Add basic type annotations

Author: tony

CHANGES

@@ -24,6 +24,7 @@ $ pipx install --suffix=@next 'tmuxp' --pip-args '\--pre' --force
 - libtmux updated from v0.12 to v0.14 {issue}`790`
 - Add [doctest](https://docs.python.org/3/library/doctest.html) w/
   [pytest + doctest](https://docs.pytest.org/en/7.1.x/how-to/doctest.html), ({issue}`791`).
+- Added basic [mypy](http://mypy-lang.org/) type annotations via {issue}`786`
 
 ## tmuxp 1.12.1 (2022-08-04)