Fix CI failure by ignoring quantreg

[yutannihilation]

It seems the latest version of quantreg requires very new Matrix package. We can ignore the error.

e.g. https://github.com/tidyverse/ggplot2/actions/runs/9044818946/job/24853881196#step:5:167

  Error: 
  ! error in pak subprocess
  Caused by error: 
  ! Could not solve package dependencies:
  * deps::.: Can't install dependency quantreg
  * quantreg: Can't install dependency MatrixModels
  * MatrixModels: Can't install dependency Matrix (>= 1.6-0)
  * Matrix: Needs R >= 4.5
  * Matrix: Needs R >= 4.4.0
  * any::sessioninfo: dependency conflict
  * any::rcmdcheck: dependency conflict

[teunbrand]

Looks good to me, thanks for keeping the CI healthy!

[yutannihilation]

Thanks for approving!