v0.16.2

Follows dirigent 0.16.2. dirigent-common, dirigent-plugin and dirigent-testing are pinned at 0.16.2.

The pack's own changes since 0.16.1:

• A tutorial: the DHIS2 half of the two-part basics course, one read from the play demo, a schema gate on the answer with the pack's formats, and a dry-run import built from the validated value, with a refusal and a transient retry in between. Every command was run for real, the UI is shown along the way, and the page is also printed to tutorial.pdf, which the published site carries.
• The classifier table in the blocks reference names 429 as transient.