Use a maintained PostgreSQL version in Docker

We're using version 13 because it's the one included in Debian Bullseye,
which is the operating system we currently use in our Dockerfile.

For consistency, we're using the same version in GitHub Actions.

Note this image requires setting a password. Otherwise we get an error:

> Database is uninitialized and superuser password is not specified.
> You must specify POSTGRES_PASSWORD to a non-empty value for the
> superuser. For example, "-e POSTGRES_PASSWORD=password" on
> "docker run".

Since now we're setting a password in the postgres service, we also need
to provide the `PGPASSWORD` environment variable (or to specify the
password in the `database.yml` file, which we do for GitLab since it
uses a separate database configuration file). Otherwise we get an error:

```
PG::ConnectionBad: connection to server at "::1", port 5432 failed:
fe_sendauth: no password supplied (PG::ConnectionBad)
```

.github/workflows/db_schema.yml

@@ -15,14 +15,15 @@ jobs:
     runs-on: ubuntu-latest
     services:
       postgres:
-        image: postgres:10.10
+        image: postgres:13.16
         ports: ["5432:5432"]
         options: --health-cmd pg_isready --health-interval 10s --health-timeout 5s --health-retries 5
         env:
           POSTGRES_USER: consul
-          POSTGRES_PASSWORD: ""
+          POSTGRES_PASSWORD: password
     env:
       PGUSER: consul
+      PGPASSWORD: password
     steps:
       - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1

.github/workflows/tests.yml

@@ -19,14 +19,15 @@ jobs:
     timeout-minutes: 60
     services:
       postgres:
-        image: postgres:10.10
+        image: postgres:13.16
         ports: ["5432:5432"]
         options: --health-cmd pg_isready --health-interval 10s --health-timeout 5s --health-retries 5
         env:
           POSTGRES_USER: consul
-          POSTGRES_PASSWORD: ""
+          POSTGRES_PASSWORD: password
     env:
       PGUSER: consul
+      PGPASSWORD: password
       RAILS_ENV: test
     strategy:
       fail-fast: false