build(deps-dev): bump lerna from 4.0.0 to 6.0.3

Bumps [lerna](https://github.com/lerna/lerna/tree/HEAD/core/lerna) from 4.0.0 to 6.0.3.
- [Release notes](https://github.com/lerna/lerna/releases)
- [Changelog](https://github.com/lerna/lerna/blob/main/core/lerna/CHANGELOG.md)
- [Commits](https://github.com/lerna/lerna/commits/v6.0.3/core/lerna)

---
updated-dependencies:
- dependency-name: lerna
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

package.json

@@ -3,7 +3,7 @@
   "private": true,
   "devDependencies": {
     "concurrently": "^7.6.0",
-    "lerna": "^4.0.0",
+    "lerna": "^6.0.3",
     "prettier": "^2.0.2",
     "tslint": "^6.1.0",
     "tslint-config-prettier": "^1.18.0",