chore(deps): update docker.io/postgres docker tag to v17

docker-compose.yml

@@ -20,7 +20,7 @@ services:
       - matrix
 
   db:
-    image: docker.io/postgres:12-alpine
+    image: docker.io/postgres:17-alpine@sha256:d388be15cfb665c723da47cccdc7ea5c003ed71f700c5419bbd075033227ce1f
     restart: unless-stopped
     environment:
       - POSTGRES_USER=${DC_MATRIX_POSTGRES_USER:-synapse}