Update changelog date

Author: mroote

CHANGELOG.md

@@ -3,7 +3,7 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
-## [0.9.0]
+## [0.9.0] 2021-01-07
 ### Added
 - Autostart factorio, when starting the server-manager - Thanks to @Psychomantis71
 
@@ -16,6 +16,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Console page is now working correctly (directly reloading still bugged until new UI) - Thanks to @jannaahs
 - Mod Search fixed by new implementation, which does not rely on the search endpoint of the mod portal - Thanks to @jannaahs
 - Listen on port 80, previously port 8080 was used. Can be changed with `--port <port>`
+- Update version numbers in Docker containers
 
 ## [0.8.2] - 2020-01-08
 Many bugfixes and a few small features in this release.