Upgrade to MongoDB 6.0.3.

Thanks to MongoDB developers!

docker-compose.yml

@@ -98,7 +98,7 @@ services:
     # Quay image does work:
     #   image: quay.io/wekan/mongo:4.4.2-bionic
     # Docker Hub MongoDB image does work:
-    image: mongo:5
+    image: mongo:6
     #-------------------------------------------------------------------------------------
     container_name: wekan-db
     restart: always

snapcraft.yaml

@@ -65,7 +65,7 @@ apps:
 
 parts:
     mongodb:
-        source: https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-ubuntu2004-5.0.14.tgz
+        source: https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-ubuntu2004-6.0.3.tgz
         plugin: dump
         stage-packages:
             - libssl1.1