fix(mui): createMuiTheme deprecation for createTheme

[thcolin]

Q	A
Branch?	stable
Tickets	-
License	MIT
Doc PR	-

Fix MUI warning on @api-platform/admin app launch about createMuiTheme usage:

Material-UI: the createMuiTheme function was renamed to createTheme.

You should use `import { createTheme } from '@material-ui/core/styles'

[alanpoulain]

Shouldn't we add it in our (peer?) dependencies with the corresponding minimal version?

[thcolin]

I don't know the best practices for this kind of peer-dependencies, @material-ui/core is a dependency from react-admin and deprecation change was made 6 month ago on @material-ui/core@5.0.3

[alanpoulain]

IMO, since we are using it directly, we should add it as a dependency too. Also, is createTheme available in MUI 4? We shouldn't drop the compatibility for MUI 4.

[thcolin]

Yes, createTheme is available in MUI 4:

https://github.com/mui-org/material-ui/blob/v4.12.3/packages/material-ui/src/styles/createTheme.js

[alanpoulain]

Thanks!