Update README.md

It's actually an array of strings

README.md

@@ -122,7 +122,7 @@ Allowed values are as follows
 |**[`showErrors`](#)**|`{Boolean}`|`true`|Errors details will be written into the HTML page|
 |**[`chunks`](#)**|`{?}`|`?`|Allows you to add only some chunks (e.g only the unit-test chunk)|
 |**[`chunksSortMode`](#plugins)**|`{String\|Function}`|`auto`|Allows to control how chunks should be sorted before they are included to the HTML. Allowed values are `'none' \| 'auto' \| 'dependency' \| 'manual' \| {Function}`|
-|**[`excludeChunks`](#)**|`{String}`|``|Allows you to skip some chunks (e.g don't add the unit-test chunk)|
+|**[`excludeChunks`](#)**|`{Array.<string>}`|``|Allows you to skip some chunks (e.g don't add the unit-test chunk)|
 |**[`xhtml`](#)**|`{Boolean}`|`false`|If `true` render the `link` tags as self-closing (XHTML compliant)|
 
 Here's an example webpack config illustrating how to use these options