Switch to automatically upgraded PostgreSQL 15 (#6185)

The pgautoupgrade repo on Docker Hub now has stable version tags, so lets use the PostgreSQL 15.x series.

.ci/docker-compose.ci.yml

@@ -19,7 +19,7 @@ services:
     image: redis:7-alpine
     restart: unless-stopped
   postgres:
-    image: pgautoupgrade/pgautoupgrade:dev
+    image: pgautoupgrade/pgautoupgrade:15-alpine3.8
     command: "postgres -c fsync=off -c full_page_writes=off -c synchronous_commit=OFF"
     restart: unless-stopped
     environment:

.ci/docker-compose.cypress.yml

@@ -68,7 +68,7 @@ services:
     image: redis:7-alpine
     restart: unless-stopped
   postgres:
-    image: pgautoupgrade/pgautoupgrade:dev
+    image: pgautoupgrade/pgautoupgrade:15-alpine3.8
     command: "postgres -c fsync=off -c full_page_writes=off -c synchronous_commit=OFF"
     restart: unless-stopped
     environment:

docker-compose.yml

@@ -52,7 +52,7 @@ services:
     image: redis:7-alpine
     restart: unless-stopped
   postgres:
-    image: pgautoupgrade/pgautoupgrade:dev
+    image: pgautoupgrade/pgautoupgrade:15-alpine3.8
     ports:
       - "15432:5432"
     # The following turns the DB into less durable, but gains significant performance improvements for the tests run (x3