Update dependency core-js to v3

Author: renovate-bot

package.json

@@ -25,7 +25,7 @@
     "@angular/platform-browser-dynamic": "6.1.10",
     "@angular/router": "6.1.10",
     "b64-to-blob": "^1.2.19",
-    "core-js": "^2.4.1",
+    "core-js": "3.20.2",
     "deepmerge": "^2.0.1",
     "dot-object": "^1.7.0",
     "fabric": "^2.2.4",