feat(Dependencies): Update dependency ng2-charts to v6

| datasource | package    | from  | to    |
| ---------- | ---------- | ----- | ----- |
| npm        | ng2-charts | 5.0.4 | 6.0.1 |

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@denbi/cloud-portal-webapp",
-  "version": "4.856.0",
+  "version": "4.857.0",
   "description": "de.NBI Cloud Portal",
   "scripts": {
     "ng": "ng serve",
@@ -60,7 +60,7 @@
     "keypairs": "1.2.14",
     "mime": "4.0.4",
     "moment": "2.30.1",
-    "ng2-charts": "5.0.4",
+    "ng2-charts": "6.0.1",
     "ng2-cookies": "1.0.12",
     "ngx-bootstrap": "18.0.2",
     "ngx-clipboard": "16.0.0",