chore(deps): update postgres:18.6-alpine docker digest to 650d7a8 (#307)

k8s/infra/postgres.yaml

@@ -53,7 +53,7 @@ spec:
     spec:
       containers:
       - name: postgres
-        image: postgres:18.6-alpine@sha256:d3e1620b530c944afa6e887d22eb899824da68e19c52024bf98f5220c88a65b2
+        image: postgres:18.6-alpine@sha256:650d7a867dc5336eff67802a1417fcc801821d73d824c608e80afbde792fe6e1
         args:
         - -c
         - shared_buffers=384MB