[Documentation] How to work with storybooks

[wh1t3h47]

Hi

I have noted that you stopped supporting webpack v4 (which honestly is old anyways), but this also broke storybooks, which needs to have a special setup to update to webpack v5.

It would be a good idea to document this issue, there are some very cryptic errors which cost me some time to understand when compiling react toastify in storybooks default setup, collecting this errors and linking it to the documentation would also help anyone that faces this issue.