chore(deps): update docker.io/postgres docker tag to v12.22

docker-compose.yml

@@ -19,7 +19,7 @@ services:
       - matrix
 
   db:
-    image: docker.io/postgres:12.21-alpine@sha256:ab3d275fff0d3848e46d7aa0e535eddca1f1d309a7af05af41e328c3986b51f7
+    image: docker.io/postgres:12.22-alpine@sha256:eb37f58646a901dc7727cf448cae36daaefaba79de33b5058dab79aa4c04aefb
     restart: unless-stopped
     environment:
       - POSTGRES_USER=${DC_MATRIX_POSTGRES_USER:-synapse}