chore: added material ui 4 import rule

Signed-off-by: Gaurav Pandey <grvpandey11@gmail.com>

.changeset/curly-snails-hammer.md

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

plugins/newrelic/.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/newrelic/src/components/NewRelicComponent/NewRelicComponent.tsx

@@ -15,7 +15,7 @@
  */
 
 import React from 'react';
-import { Grid } from '@material-ui/core';
+import Grid from '@material-ui/core/Grid';
 import NewRelicFetchComponent from '../NewRelicFetchComponent';
 import {
   Header,