Upgrade docs to include steps for upgrading to latest version.

[jibin362]

Feature request

Is your feature request related to a problem? Please describe.

We have an older version of React Storefront running. Lately with all the developments done, the never version of storefront has breaking dependency changes (for eg., @material-ui v4 was changed to @mui v5, Next.js 10.x to 12.x etc..).

Describe the solution you'd like

A clear and concise documentation on things to consider while upgrading to latest version. Steps on how to upgrade etc.. would be of great help as a separate section in the docs. Something similar to https://nextjs.org/docs/upgrading

Describe alternatives you've considered

None yet.