Upgrade dependencies (#469)

The customary pre-release dep bumps for the v0.7.0 release.

Upgrades:
- hashbrown from 0.15 to 0.16
- roxmltree from 0.20 to 0.21
- Patch versions to latest for all dependencies

This PR intentionally does not upgrade fontations as we will want to
sync that with Vello and the fixes in the latest version are not high
priority for us.

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Signed-off-by: Nico Burns <nico@nicoburns.com>

Author: nicoburns