Update dependency @babel/core to v7.6.4

Author: renovate-bot

src/React.Core/package-lock.json

@@ -6,7 +6,7 @@
     "build": "webpack"
   },
   "devDependencies": {
-    "@babel/core": "7.6.3",
+    "@babel/core": "7.6.4",
     "@babel/standalone": "7.6.3",
     "prop-types": "15.7.2",
     "react": "16.10.2",

src/React.Core/package.json

@@ -20,7 +20,7 @@
     "styled-components": "^4.0.0"
   },
   "devDependencies": {
-    "@babel/core": "7.6.3",
+    "@babel/core": "7.6.4",
     "@babel/plugin-proposal-class-properties": "7.5.5",
     "@babel/plugin-proposal-object-rest-spread": "7.6.2",
     "@babel/plugin-syntax-dynamic-import": "7.2.0",