Auto merge of #3982 - pietroalbini:pg13, r=Turbo87

Bump CI to PostgreSQL 13

This PR bumps CI's PostgreSQL to version 13, to match what we will upgrade to tomorrow.

Author: bors

.github/workflows/ci.yml

@@ -133,7 +133,7 @@ jobs:
 
     services:
       postgres:
-        image: postgres:11
+        image: postgres:13
         env:
           POSTGRES_PASSWORD: postgres
         # Set health checks to wait until postgres has started