[docs] Recommend yarn link to test local distribution (#13348)
[docs] Recommend yarn link to test local distribution (#13348)

* Recommend yarn link to test local distribution

In this commit, we are updating the CONTRIBUTING file to recommend using
"yarn link" to test the local distribution of Material-UI.

This approach was discussed in #13312

* Empty commit to force codecov to work

rscnt/material-ui,mui-org/material-ui,Kagami/material-ui,oliviertassinari/material-ui,mui-org/material-ui,oliviertassinari/material-ui,kybarg/material-ui,oliviertassinari/material-ui,Kagami/material-ui,mbrookes/material-ui,mui-org/material-ui,callemall/material-ui,kybarg/material-ui,Kagami/material-ui,callemall/material-ui,callemall/material-ui,mbrookes/material-ui,callemall/material-ui,rscnt/material-ui,lgollut/material-ui,Kagami/material-ui,kybarg/material-ui,allanalexandre/material-ui,rscnt/material-ui,kybarg/material-ui,mbrookes/material-ui