Update dependency core-js to v3.15.2 (#4515)

Co-authored-by: Renovate Bot <[email protected]>

Author: renovate[bot]

package-lock.json

@@ -136,7 +136,7 @@
 		"chalk": "4.1.1",
 		"circular-dependency-plugin": "5.2.2",
 		"commander": "6.2.1",
-		"core-js": "3.8.3",
+		"core-js": "3.15.2",
 		"create-file-webpack": "1.0.2",
 		"cross-env": "6.0.3",
 		"cssnano": "4.1.11",