Merge pull request #580 from saulotoledo/Contrib

Updated Contribution Guidelines.

CONTRIBUTING.md

@@ -13,7 +13,7 @@ Also, please ensure your pull request adheres to the following guidelines:
 * Software that is PHP 5.5+, Composer-installable, PSR compliant, semantically versioned, united tested and well documented in English is preferred.
 * Please search previous suggestions before making a new one, as yours may be a duplicate.
 * Enter a meaningful pull request description.
-* Please make an individual commit for each suggestion in a pull request.
+* Please make an individual commit for each suggestion in a separate pull request.
 * Put a link to each library in your pull request ticket so it's easier to review.
 * Use the following format for libraries: \[LIBRARY\]\(LINK\) - DESCRIPTION.
 * Prefix duplicate library names with their vendor or namespace followed by a space: Foo\Bar would be Foo Bar.