Bump core-js from 3.18.2 to 3.20.3

Bumps [core-js](https://github.com/zloirock/core-js) from 3.18.2 to 3.20.3.
- [Release notes](https://github.com/zloirock/core-js/releases)
- [Changelog](https://github.com/zloirock/core-js/blob/master/CHANGELOG.md)
- [Commits](https://github.com/zloirock/core-js/compare/v3.18.2...v3.20.3)

---
updated-dependencies:
- dependency-name: core-js
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

package.json

@@ -29,7 +29,7 @@
     "browserify-sign": "^4.2.1",
     "clone-deep": "^4.0.1",
     "compare-versions": "^4",
-    "core-js": "^3.18.2",
+    "core-js": "^3.20.3",
     "cross-env": "7.0.3",
     "css-loader": "^6.5.1",
     "deep-equal": "2.0.5",