chore: upgrade ghost to 6.57.1-alpine

Reviewed-on: https://git.coopcloud.tech/coop-cloud/ghost/pulls/13

README.md

@@ -32,4 +32,4 @@ Node.js CMS for professional publishing (headless possible).
 
 ## Further configuration
 ### Matrix-Synapse configuration
-If you want to use Ghost on a top-level-domain which you want to use as matrix server name as well, just uncomment the respective section in `YOURAPPDOMAIN.env` and insert your `MATRIX_DOMAIN`
+If you want to use Ghost on a top-level-domain which you want to use as matrix server name as well, just uncomment the respective section in `YOURAPPDOMAIN.env` and insert your `MATRIX_DOMAIN`

compose.yml

@@ -1,6 +1,6 @@
 services:
   app:
-    image: ghost:6.45.0-alpine
+    image: ghost:6.57.1-alpine
     environment:
       # see https://ghost.org/docs/config/#configuration-options
       database__client: mysql