Added Material UI 4 import rule to plugins/kubernetes

Signed-off-by: Aditya Kumar <aditya.kumar60@infosys.com>

.changeset/pink-zoos-own.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-kubernetes': patch
+---
+
+Added an optional ESLint rule - no-top-level-material-ui-4-imports -in kubernetes plugin which has an auto fix function to migrate the imports and used it to migrate the Material UI imports for plugins/kubernetes.

plugins/kubernetes/.eslintrc.js

@@ -1 +1,5 @@
-module.exports = require('@backstage/cli/config/eslint-factory')(__dirname);
+module.exports = require('@backstage/cli/config/eslint-factory')(__dirname, {
+    rules: {
+      '@backstage/no-top-level-material-ui-4-imports': 'error',
+    },
+  });

plugins/kubernetes/src/KubernetesContent.tsx

@@ -15,7 +15,8 @@
  */
 
 import React from 'react';
-import { Grid, Typography } from '@material-ui/core';
+import Grid from '@material-ui/core/Grid';
+import Typography from '@material-ui/core/Typography';
 import { Entity } from '@backstage/catalog-model';
 import {
   ErrorPanel,

plugins/kubernetes/src/Router.tsx

@@ -22,7 +22,7 @@ import {
 } from '@backstage/plugin-catalog-react';
 import { Route, Routes } from 'react-router-dom';
 import { KubernetesContent } from './KubernetesContent';
-import { Button } from '@material-ui/core';
+import Button from '@material-ui/core/Button';
 
 const KUBERNETES_ANNOTATION = 'backstage.io/kubernetes-id';
 const KUBERNETES_LABEL_SELECTOR_QUERY_ANNOTATION =