Update Unity Software Additional Terms to February 21, 2018 version

Author: Legal Notices

README.md

@@ -6,5 +6,6 @@ From time to time, Unity may update these software terms and other legal terms,
 
 ## Revisions
 ### Unity Software Additional Terms
-* [November 04, 2016 - Current](Unity%20Software%20Additional%20Terms.md)
+* [February 21, 2018 - Current](Unity%20Software%20Additional%20Terms.md)
+* [November 04, 2016](../45e7734/Unity%20Software%20Additional%20Terms.md)
 * [June 28, 2016](../5a5b11e/Unity%20Software%20Additional%20Terms.md)