Downgraded sass-loader to fix a compatibility issue with 8.x. See issue vuejs/vue-cli#4513

Author: robere2

packages/glimpse-ui/package-lock.json

@@ -70,7 +70,7 @@
     "jest-serializer-vue": "^2.0.2",
     "node-sass": "^4.14.1",
     "nyc": "^15.1.0",
-    "sass-loader": "^8.0.2",
+    "sass-loader": "^7.3.1",
     "sinon": "^7.5.0",
     "ts-jest": "^24.3.0",
     "vue": "latest",