Update postgres Docker tag to v16.6 (#32)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

plausible/docker-compose.yml

@@ -7,7 +7,7 @@ networks:
 services:
   plausible_db:
     restart: unless-stopped
-    image: postgres:16.5-alpine@sha256:0366402213df5db03c47ff80bcc697e92c8be0c213d03c941df1fc42d1ba9560
+    image: postgres:16.6-alpine@sha256:52bba373df3c13594014b5e9ccc9f3c2cdb2221d50db1a91ec64570819f18aba
     volumes:
       - /home/aosus/plausible/postgres:/var/lib/postgresql/data
     environment: