remove labs package

Signed-off-by: Emma Indal <emma.indahl@gmail.com>

plugins/stack-overflow/package.json

@@ -28,7 +28,6 @@
     "@backstage/theme": "^0.2.14",
     "@material-ui/core": "^4.12.2",
     "@material-ui/icons": "^4.9.1",
-    "@material-ui/lab": "4.0.0-alpha.57",
     "qs": "^6.10.3",
     "cross-fetch": "^3.0.6",
     "lodash": "^4.17.21",