fix: frontend/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-AJV-584908
- https://snyk.io/vuln/SNYK-JS-ANSIREGEX-1583908
- https://snyk.io/vuln/SNYK-JS-FSTREAM-174725
- https://snyk.io/vuln/SNYK-JS-HAWK-2808852
- https://snyk.io/vuln/SNYK-JS-INFLIGHT-6095116
- https://snyk.io/vuln/SNYK-JS-INI-1048974
- https://snyk.io/vuln/SNYK-JS-JSONSCHEMA-1920922
- https://snyk.io/vuln/SNYK-JS-MINIMATCH-3050818
- https://snyk.io/vuln/SNYK-JS-MINIMIST-2429795
- https://snyk.io/vuln/SNYK-JS-MINIMIST-559764
- https://snyk.io/vuln/SNYK-JS-QS-3153490
- https://snyk.io/vuln/SNYK-JS-REQUEST-3361831
- https://snyk.io/vuln/SNYK-JS-SEMVER-3247795
- https://snyk.io/vuln/SNYK-JS-TAR-1536528
- https://snyk.io/vuln/SNYK-JS-TAR-1536531
- https://snyk.io/vuln/SNYK-JS-TAR-1536758
- https://snyk.io/vuln/SNYK-JS-TAR-1579147
- https://snyk.io/vuln/SNYK-JS-TAR-1579152
- https://snyk.io/vuln/SNYK-JS-TAR-1579155
- https://snyk.io/vuln/SNYK-JS-TAR-174125
- https://snyk.io/vuln/SNYK-JS-TOUGHCOOKIE-5672873
- https://snyk.io/vuln/npm:debug:20170905
- https://snyk.io/vuln/npm:deep-extend:20180409
- https://snyk.io/vuln/npm:extend:20180424
- https://snyk.io/vuln/npm:hoek:20180212
- https://snyk.io/vuln/npm:sshpk:20180409
- https://snyk.io/vuln/npm:stringstream:20180511
- https://snyk.io/vuln/npm:tough-cookie:20170905

frontend/package.json

@@ -33,7 +33,7 @@
     "@angular/platform-browser": "5.2.3",
     "@angular/platform-browser-dynamic": "5.2.3",
     "@angular/router": "5.2.3",
-    "@angular-devkit/core": "^0.0.29",
+    "@angular-devkit/core": "^8.0.0",
     "@ngx-translate/core": "9.0.2",
     "@ngx-translate/http-loader": "^2.0",
     "angular2-notifications": "^0.9.7",