set postgres container to v17 to match python:3.12 container pg_dump version

Author: alistairewj

.github/workflows/build-psql.yml

@@ -11,7 +11,7 @@ jobs:
 
     services:
       postgres:
-        image: postgres
+        image: postgres:17
         env:
           POSTGRES_PASSWORD: postgres
         options: >-

.github/workflows/concepts-psql.yml

@@ -12,7 +12,7 @@ jobs:
 
     services:
       postgres:
-        image: postgres
+        image: postgres:17
         env:
           POSTGRES_PASSWORD: postgres
         options: >-

.github/workflows/equivalence.yml

@@ -16,7 +16,7 @@ jobs:
 
     services:
       postgres:
-        image: postgres
+        image: postgres:17
         env:
           POSTGRES_PASSWORD: postgres
         options: >-