gi-webkit2webextension-4.0.16: ChangeLog.md

### 4.0.16

+ Remove enable-overloading flags, and use instead explicit CPP checks for 'haskell-gi-overloading-1.0', see [how to disable overloading](https://github.com/haskell-gi/haskell-gi/wiki/Overloading\#disabling-overloading).

### 4.0.15

+ Add a dependency on gi-gio.