[material-ui][docs] Update the installation commands to use @next

[wapgear]

Use @next branch for @mui/icons-material package and for @mui/material with styled-components as well

npm ERR! code ERESOLVE
npm ERR! ERESOLVE unable to resolve dependency tree

npm ERR! Found: @mui/material@6.0.0-alpha.3
npm ERR! node_modules/@mui/material
npm ERR!   @mui/material@"^6.0.0-alpha.3" from the root project
npm ERR! 
npm ERR! Could not resolve dependency:
npm ERR! peer @mui/material@"^5.0.0" from @mui/icons-material@5.15.15
npm ERR! node_modules/@mui/icons-material
npm ERR!   @mui/icons-material@"*" from the root project

• [x] I have followed (at least) the PR section of the contributing guide.

[wapgear]

Seems fine to me! Thanks for your first contribution! 🤝

Hey @danilo-leal. What should be my next steps to get it merged? Did I miss something?