Update babel monorepo to v7.6.4

Author: renovate-bot

package-lock.json

@@ -38,8 +38,8 @@
     "@types/testing-library__react-hooks": "^2.0.0"
   },
   "devDependencies": {
-    "@babel/cli": "7.6.3",
-    "@babel/core": "7.6.3",
+    "@babel/cli": "7.6.4",
+    "@babel/core": "7.6.4",
     "@babel/plugin-proposal-object-rest-spread": "7.6.2",
     "@babel/plugin-transform-modules-commonjs": "7.6.0",
     "@babel/plugin-transform-runtime": "7.6.2",