Bump core-js from 2.6.12 to 3.9.1

Bumps [core-js](https://github.com/zloirock/core-js/tree/HEAD/packages/core-js) from 2.6.12 to 3.9.1.
- [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/commits/v3.9.1/packages/core-js)

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

package.json

@@ -45,7 +45,7 @@
     "@types/mongoose": "^5.10.3",
     "@types/pino": "^6.3.6",
     "babel-jest": "^26.6.3",
-    "core-js": "^2.6.12",
+    "core-js": "^3.9.1",
     "eslint": "^7.21.0",
     "eslint-config-airbnb-base": "^14.2.1",
     "eslint-plugin-import": "^2.22.1",