Website: testing tutorial shows the database attribute once 1.14.0 is released

[zantvoort]

The testing tutorial on the site (website/src/pages/tutorials/testing.js) shows the static dataSource() + @Testcontainers setup for running @StormTest against PostgreSQL. With #502 (PR #509) the same step is one attribute, @StormTest(database = POSTGRESQL, ...).

The site deploys from main on every push, so the tutorial cannot change before the v1.14.0 tag without advertising an unreleased API. PR #510 holds the change as a draft.

Steps on release day

1. Push the v1.14.0 tag; wait for release.yml to push its "docs: snapshot version 1.14.0" commit.
2. Mark docs: testing tutorial uses the database attribute (merge after v1.14.0) #510 ready and merge it.

Closing this issue is part of closing the 1.14.0 milestone.