Fix error in rules list in README (fixes #371)

Author: yannickcr

README.md

@@ -71,7 +71,6 @@ Finally, enable all of the rules that you would like to use.
     "react/jsx-max-props-per-line": 1,
     "react/jsx-no-bind": 1,
     "react/jsx-no-duplicate-props": 1,
-    "react/jsx-no-is-mounted": 1,
     "react/jsx-no-literals": 1,
     "react/jsx-no-undef": 1,
     "react/jsx-pascal-case": 1,
@@ -85,6 +84,7 @@ Finally, enable all of the rules that you would like to use.
     "react/no-did-mount-set-state": 1,
     "react/no-did-update-set-state": 1,
     "react/no-direct-mutation-state": 1,
+    "react/no-is-mounted": 1,
     "react/no-multi-comp": 1,
     "react/no-set-state": 1,
     "react/no-string-refs": 1,