fix: upgrade @mui/material from 6.0.0-rc.0 to 6.0.0

Snyk has created this PR to upgrade @mui/material from 6.0.0-rc.0 to 6.0.0.

See this package in npm:
@mui/material

See this project in Snyk:
https://app.snyk.io/org/shagg0r/project/46efcee7-876f-4b97-ac1e-f84a11480552?utm_source=github&utm_medium=referral&page=upgrade-pr

examples/material-ui-express-ssr/package.json

@@ -15,7 +15,7 @@
     "@emotion/react": "latest",
     "@emotion/styled": "latest",
     "@emotion/server": "latest",
-    "@mui/material": "next",
+    "@mui/material": "6.0.0",
     "babel-loader": "latest",
     "cross-env": "latest",
     "express": "latest",