Deps: Update caddy Docker tag to v2.11

Author: renovate[bot]

docker/Dockerfile

@@ -111,7 +111,7 @@ RUN set -eux; \
 RUN rm -f .env.local.php
 
 # Caddy image
-FROM caddy:2.10 AS app_caddy
+FROM caddy:2.11 AS app_caddy
 
 WORKDIR /srv/spirit-web-twig-demo