Downgrade lerna-changelog because it has a bug

Author: gaearon

package.json

@@ -27,7 +27,7 @@
     "husky": "1.0.0-rc.15",
     "jest": "^23.6.0",
     "lerna": "2.9.1",
-    "lerna-changelog": "^0.8.0",
+    "lerna-changelog": "^0.7.0",
     "lint-staged": "^7.0.5",
     "meow": "^5.0.0",
     "multimatch": "^2.1.0",