chore: set utc timezone in examples

Author: openscript

examples/public/docker-compose.yaml

@@ -41,6 +41,7 @@ services:
       - database
     environment:
       LANG: C.UTF-8
+      TZ: UTC
       CORS_ORIGIN: https://test.example.com
       SESSION_SECRET: secret
       SESSION_SALT: salt
@@ -66,6 +67,7 @@ services:
       - database:/var/lib/postgresql/data
     environment:
       POSTGRES_PASSWORD: "secret"
+      PGTZ: "UTC"
 
   frontend:
     image: ghcr.io/openscript-ch/quassel-frontend:latest