Bump core-js from 3.14.0 to 3.15.0 (forem#14026)

Bumps [core-js](https://github.com/zloirock/core-js/tree/HEAD/packages/core-js) from 3.14.0 to 3.15.0.
- [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/commits/v3.15.0/packages/core-js)

---
updated-dependencies:
- dependency-name: core-js
  dependency-type: direct:production
  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>

yarn.lock

@@ -6814,9 +6814,9 @@ core-js-pure@^3.8.2:
   integrity sha512-CC582enhrFZStO4F8lGI7QL3SYx7/AIRc+IdSi3btrQGrVsTawo5K/crmKbRrQ+MOMhNX4v+PATn0k2NN6wI7A==
 
 core-js@3, core-js@^3.0.1, core-js@^3.0.4, core-js@^3.12.1, core-js@^3.6.5, core-js@^3.8.2:
-  version "3.14.0"
-  resolved "https://registry.yarnpkg.com/core-js/-/core-js-3.14.0.tgz#62322b98c71cc2018b027971a69419e2425c2a6c"
-  integrity sha512-3s+ed8er9ahK+zJpp9ZtuVcDoFzHNiZsPbNAAE4KXgrRHbjSqqNN6xGSXq6bq7TZIbKj4NLrLb6bJ5i+vSVjHA==
+  version "3.15.0"
+  resolved "https://registry.yarnpkg.com/core-js/-/core-js-3.15.0.tgz#db9554ebce0b6fd90dc9b1f2465c841d2d055044"
+  integrity sha512-GUbtPllXMYRzIgHNZ4dTYTcUemls2cni83Q4Q/TrFONHfhcg9oEGOtaGHfb0cpzec60P96UKPvMkjX1jET8rUw==
 
 core-js@^2.4.0, core-js@^2.5.0:
   version "2.6.12"