add CSSProperties type for panelCSS

Signed-off-by: Chongyang Adrian, Ke <ftt.adrian.ke@grabtaxi.com>

plugins/techdocs/package.json

@@ -41,6 +41,7 @@
     "@material-ui/core": "^4.11.0",
     "@material-ui/icons": "^4.9.1",
     "@material-ui/lab": "4.0.0-alpha.45",
+    "@material-ui/styles": "^4.10.0",
     "react": "^16.13.1",
     "react-dom": "^16.13.1",
     "react-router": "6.0.0-beta.0",

plugins/techdocs/src/home/components/TechDocsCustomHome.tsx

@@ -17,7 +17,7 @@
 import React, { useState } from 'react';
 import { useAsync } from 'react-use';
 import { makeStyles } from '@material-ui/core';
-
+import { CSSProperties } from '@material-ui/styles';
 import { catalogApiRef, CatalogApi } from '@backstage/plugin-catalog-react';
 import { Entity } from '@backstage/catalog-model';
 import {
@@ -48,7 +48,7 @@ export interface PanelConfig {
   title: string;
   description: string;
   panelType: PanelType;
-  panelCSS?: {};
+  panelCSS?: CSSProperties;
   filterPredicate: (entity: Entity) => boolean;
 }