Fixed medium security issue

Dockerfile

@@ -4,7 +4,7 @@ FROM alpine:3.11
 ENV PATH="/mattermost/bin:${PATH}"
 
 # Picasoft : change these values. The team version is used by default
-ENV MM_VERSION=6.2.1
+ENV MM_VERSION=6.2.2
 
 # Get these ids with the output of `id mattermost` on the VM hosting the app
 ARG PUID=5000