turn on max empty line rule with default of max: 2. (#3176)

Run with fix.

.eslintrc.json

@@ -18,6 +18,7 @@
         "linebreak-style": ["error", "unix"],
         "no-trailing-spaces": 2,
         "eol-last": 2,
-        "space-in-parens": ["error", "never"]
+        "space-in-parens": ["error", "never"],
+        "no-multiple-empty-lines": 1
     }
 }