demo(package): updated @angular/pwa

Author: AnthonyNahas

demo/package-lock.json

@@ -29,7 +29,7 @@
     "@angular/platform-browser": "^6.1.9",
     "@angular/platform-browser-dynamic": "^6.1.9",
     "@angular/platform-server": "^6.1.9",
-    "@angular/pwa": "^0.7.5",
+    "@angular/pwa": "^0.8.4",
     "@angular/router": "^6.1.9",
     "@angular/service-worker": "^6.1.9",
     "@ng-bootstrap/ng-bootstrap": "^2.2.2",
@@ -95,4 +95,4 @@
     ],
     "setupTestFrameworkScriptFile": "<rootDir>/src/setupJest.ts"
   }
-}
+}