graphics/oculante: update to 0.6.8

0.6.8 (2022-09-07)
Bug Fixes
- Remove offset when initially clicking into OSX window (81544cc4)

Features
- Persistent settings support. Vsync and color theme are now customizable.
  (21ed3954)

Chore
- Update psd, ext, dds-rs (ad2f531b)

0.6.7 (2022-09-06)
Bug Fixes
- Disable image center on window resize, as this caused jumping (ee557d47)

Features
- Add Posterize image effect (3e019728)
- Equalize image operator added (748bf15e)
- Allow editing the export image extension to save as a different image format
  (23519eee)

(pin)