Change naming from singular defaultProp to plural defaultProps

lib/rules/require-default-props.js

@@ -37,7 +37,7 @@ module.exports = {
 
 
     /**
-     * Reports all propTypes passed in that don't have a defaultProp counterpart.
+     * Reports all propTypes passed in that don't have a defaultProps counterpart.
      * @param  {Object[]} propTypes    List of propTypes to check.
      * @param  {Object}   defaultProps Object of defaultProps to check. Keys are the props names.
      * @return {void}
@@ -55,7 +55,7 @@ module.exports = {
           if (forbidDefaultForRequired && defaultProps[propName]) {
             context.report(
               prop.node,
-              'propType "{{name}}" is required and should not have a defaultProp declaration.',
+              'propType "{{name}}" is required and should not have a defaultProps declaration.',
               {name: propName}
             );
           }
@@ -68,7 +68,7 @@ module.exports = {
 
         context.report(
           prop.node,
-          'propType "{{name}}" is not required, but has no corresponding defaultProp declaration.',
+          'propType "{{name}}" is not required, but has no corresponding defaultProps declaration.',
           {name: propName}
         );
       });