0.20 has a bunch of bugs that will be fixed by:
* https://github.com/gfx-rs/wgpu/pull/5681
At Rerun, we don't want to wait for the wgpu 0.20.1 patch release before
we update egui, so we will temporarily downgrade to wgpu 0.19
After reverting I'll open a new PR that will update to 0.20 again, with
the intention of merging that once 0.20.1 is released.