Update changelogs

Author: franvis

CHANGES.md

@@ -10,6 +10,7 @@ This document is intended for Spotless developers.
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `1.27.0`).
 
 ## [Unreleased]
+* Bump default ktfmt from 0.15 to 0.16, and remove duplicated logic for the --dropbox-style option ([#642](https://github.com/diffplug/spotless/pull/648))
 
 ## [2.2.0] - 2020-07-13
 ### Added

plugin-gradle/CHANGES.md

@@ -3,6 +3,7 @@
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `3.27.0`).
 
 ## [Unreleased]
+* Bump default ktfmt from 0.15 to 0.16, and remove duplicated logic for the --dropbox-style option ([#642](https://github.com/diffplug/spotless/pull/648))
 
 ## [5.1.0] - 2020-07-13
 ### Added

plugin-maven/CHANGES.md

@@ -4,7 +4,7 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 
 ## [Unreleased]
 ### Changes
-*  Bump default ktfmt from 0.13 to 0.15 ([#641](https://github.com/diffplug/spotless/issues/641)).
+*  Bump default ktfmt from 0.13 to 0.16 ([#642](https://github.com/diffplug/spotless/pull/648)).
 
 ## [2.0.1] - 2020-07-04
 ### Fixed