Bump core-js from 2.6.5 to 3.3.6 (#58)

Bumps [core-js](https://github.com/zloirock/core-js) from 2.6.5 to 3.3.6.
- [Release notes](https://github.com/zloirock/core-js/releases)
- [Changelog](https://github.com/zloirock/core-js/blob/master/CHANGELOG.md)
- [Commits](zloirock/core-js@v2.6.5...v3.3.6)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Author: dependabot-preview[bot]

package.json

@@ -22,7 +22,7 @@
     "electron-context-menu": "0.15.0",
     "electron-updater": "4.1.2",
     "element-ui": "2.12.0",
-    "core-js": "2.6.5",
+    "core-js": "3.3.6",
     "vue": "2.6.10",
     "vue-router": "3.1.2"
   },