chore(package): update @angular-builders/jest to version 8.3.1

Closes #90

Author: greenkeeper[bot]

demo/package.json

@@ -51,7 +51,7 @@
     "zone.js": "^0.8.26"
   },
   "devDependencies": {
-    "@angular-builders/jest": "^7.2.0",
+    "@angular-builders/jest": "^8.3.1",
     "@angular-devkit/build-angular": "^0.10.7",
     "@angular-devkit/schematics": "^7.2.1",
     "@angular/cli": "^7.2.1",