chore(deps): update ghcr.io/it-at-m/refarch/refarch-gateway docker tag to v1.6.0

Author: renovate[bot]

stack/docker-compose.yml

@@ -96,7 +96,7 @@ services:
     security_opt: *security_settings
 
   refarch-gateway:
-    image: ghcr.io/it-at-m/refarch/refarch-gateway:1.4.5@sha256:7aa12dd012ab96da2053c509c9c957bc1a1548bcba295a563dc2f0d5bab985f0
+    image: ghcr.io/it-at-m/refarch/refarch-gateway:1.6.0@sha256:df27f73a72c42f15e7d37267b2b726e70cc917bcf8b03f0b275787715477acae
     depends_on:
       init-keycloak:
         condition: service_completed_successfully