Update CHANGELOG

Author: magni-

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 #### Fixes
 
+* [#840](https://github.com/ruby-grape/grape-swagger/pull/840): Fixes documentation of `additionalProperties` field when used with array parameters, or when setting it to `false` - [@magni-](https://github.com/magni-)
 * [#841](https://github.com/ruby-grape/grape-swagger/pull/839): Fixes `type` and `format` values for object fields nested in an array ([#832](https://github.com/ruby-grape/grape-swagger/issue/832)) - [@magni-](https://github.com/magni-)
 * [#839](https://github.com/ruby-grape/grape-swagger/pull/839): Fixes documentation of `false` or `nil` default parameter values - [@magni-](https://github.com/magni-)
 * Your contribution here.

UPGRADING.md

@@ -1,5 +1,9 @@
 ## Upgrading Grape-swagger
 
+### Upgrading to >= 1.4.1
+
+- `additionalProperties` has been deprecated and will be removed in a future version of `grape-swagger`. It has been replaced with `additional_properties`.
+
 ### Upgrading to >= 1.4.0
 
 - Official support for ruby < 2.5 removed, ruby 2.5 only in testing mode, but no support.