Auto merge of #20067 - Eijebong:clipboard, r=nox

Update clipboard related dependencies to use xcb 0.8

See https://github.com/rtbo/rust-xcb/pull/55

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/20067)
<!-- Reviewable:end -->

Author: bors-servo