graphics/d2: Update to 0.9.0
This is a significant release. Until now, D2 shipped with the ELK
and Dagre layout engines, but TALA was closed-source and required
a paid subscription.
Just a day or two ago, D2 announced that they are shutting down
their subscription service (and the online editor for D2 diagrams.)
This release now includes the TALA engine, and no license key is
required to use it. At some point, the Terrastruct D2 editor is
expected to be open-sourced.