Update lerna requirement from ^3.16.4 to ^3.18.4

Updates the requirements on [lerna](https://github.com/lerna/lerna/tree/HEAD/core/lerna) to permit the latest version.
- [Release notes](https://github.com/lerna/lerna/releases)
- [Changelog](https://github.com/lerna/lerna/blob/master/core/lerna/CHANGELOG.md)
- [Commits](https://github.com/lerna/lerna/commits/v3.18.4/core/lerna)

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

package.json

@@ -23,7 +23,7 @@
     "kotlin": "^1.3.50",
     "kotlinx-coroutines-core": "^1.3.2",
     "kotlinx-html": "^0.6.12",
-    "lerna": "^3.16.4",
+    "lerna": "^3.18.4",
     "lerna-changelog": "^0.8.2",
     "lint-staged": "^9.4.3",
     "prettier": "^1.18.2",