Bump core-js from 3.20.3 to 3.21.1 (#4970)

Bumps [core-js](https://github.com/zloirock/core-js) from 3.20.3 to 3.21.1.
- [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/v3.20.3...v3.21.1)

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

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -13,7 +13,7 @@
     "babel-plugin-istanbul": "6.1.1",
     "comma-separated-values": "3.6.4",
     "copy-webpack-plugin": "10.2.0",
-    "core-js": "3.20.3",
+    "core-js": "3.21.1",
     "cross-env": "7.0.3",
     "css-loader": "4.0.0",
     "d3-axis": "1.0.x",