fix: package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-ASYNC-7414156
- https://snyk.io/vuln/SNYK-JS-SERIALIZEJAVASCRIPT-6147607

package.json

@@ -111,9 +111,9 @@
     "@vue/cli-plugin-babel": "4.5.15",
     "@vue/cli-plugin-e2e-nightwatch": "5.0.6",
     "@vue/cli-plugin-eslint": "4.5.15",
-    "@vue/cli-plugin-pwa": "4.5.15",
+    "@vue/cli-plugin-pwa": "5.0.0",
     "@vue/cli-plugin-unit-jest": "4.5.15",
-    "@vue/cli-service": "4.5.15",
+    "@vue/cli-service": "5.0.1",
     "@vue/eslint-config-prettier": "6.0.0",
     "@vue/test-utils": "1.3.0",
     "apollo": "2.34.0",