chore(deps): update dependency lerna to v6

Author: renovate[bot]

package.json

@@ -32,7 +32,7 @@
     "ava": "3.8.2",
     "coveralls": "3.1.0",
     "graphql": "14.6.0",
-    "lerna": "3.22.0",
+    "lerna": "6.6.1",
     "nyc": "15.1.0",
     "standard": "14.3.4",
     "ts-node": "8.10.2",