build(deps): bump @material-ui/core from 3.9.2 to 3.9.3

Bumps [@material-ui/core](https://github.com/mui-org/material-ui) from 3.9.2 to 3.9.3.
- [Release notes](https://github.com/mui-org/material-ui/releases)
- [Changelog](https://github.com/mui-org/material-ui/blob/v3.9.3/CHANGELOG.md)
- [Commits](mui/material-ui@v3.9.2...v3.9.3)

Signed-off-by: dependabot[bot] <support@dependabot.com>

Author: dependabot-support