chore(apps): update icons (#3156)

* chore(apps): update icons

* bump everything

charts/stable/mattermost/Chart.yaml

@@ -10,7 +10,7 @@ dependencies:
   version: 8.0.30
 description: Mattermost is an open source platform for secure collaboration across the entire software development lifecycle.
 home: https://github.com/truecharts/apps/tree/master/charts/stable/mattermost
-icon: https://truecharts.org/img/appicons/mattermost.png
+icon: https://truecharts.org/img/chart-icons/mattermost.png
 keywords:
 - team
 - mattermost
@@ -24,7 +24,7 @@ name: mattermost
 sources:
 - https://github.com/mattermost/mattermost-server
 - https://github.com/mattermost/docker
-version: 3.0.15
+version: 3.0.16
 annotations:
   truecharts.org/catagories: |
     - hosting