chore: bump the version of material-ui core to 4.12.2

Signed-off-by: blam <ben@blam.sh>

packages/test-utils/package.json

@@ -33,7 +33,7 @@
     "@backstage/core-plugin-api": "^0.1.3",
     "@backstage/test-utils-core": "^0.1.1",
     "@backstage/theme": "^0.2.8",
-    "@material-ui/core": "^4.11.0",
+    "@material-ui/core": "^4.12.2",
     "@testing-library/jest-dom": "^5.10.1",
     "@testing-library/react": "^11.2.5",
     "@testing-library/user-event": "^13.1.8",