Added Material UI 4 import rule to plugins/fossa

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

plugins/fossa/.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/fossa/dev/index.tsx

@@ -21,7 +21,7 @@ import {
   catalogApiRef,
   EntityProvider,
 } from '@backstage/plugin-catalog-react';
-import { Grid } from '@material-ui/core';
+import Grid from '@material-ui/core/Grid';
 import React from 'react';
 import { EntityFossaCard, fossaPlugin } from '../src';
 import { FindingSummary, FossaApi, fossaApiRef } from '../src/api';

plugins/fossa/src/components/FossaCard/FossaCard.tsx

@@ -18,7 +18,8 @@ import {
   useEntity,
   MissingAnnotationEmptyState,
 } from '@backstage/plugin-catalog-react';
-import { Grid, Tooltip } from '@material-ui/core';
+import Grid from '@material-ui/core/Grid';
+import Tooltip from '@material-ui/core/Tooltip';
 import { makeStyles } from '@material-ui/core/styles';
 import Typography from '@material-ui/core/Typography';
 import { DateTime } from 'luxon';

plugins/fossa/src/components/FossaPage/FossaPage.tsx

@@ -26,9 +26,9 @@ import {
   humanizeEntityRef,
   getEntityRelations,
 } from '@backstage/plugin-catalog-react';
-import { Tooltip } from '@material-ui/core';
+import Tooltip from '@material-ui/core/Tooltip';
 import Typography from '@material-ui/core/Typography';
-import { Skeleton } from '@material-ui/lab';
+import Skeleton from '@material-ui/lab/Skeleton';
 import { DateTime } from 'luxon';
 import * as React from 'react';
 import { useMemo, useState } from 'react';