Added lerna dependency to SDK repo

no issue
We use lerna for monorepo functions within this project, this allows test, ship etc to run without having lerna installed globally

Author: sam-lord

package.json

@@ -22,6 +22,7 @@
     "eslint": "8.39.0",
     "eslint-plugin-ghost": "2.16.0",
     "eslint-plugin-react": "7.32.2",
+    "lerna": "6.6.2",
     "mocha": "10.2.0",
     "should": "13.2.3",
     "sinon": "15.0.4"