Fix thanks message

Author: MadLittleMods

CHANGELOG.md

@@ -3,7 +3,7 @@
 # v0.5.2 - 2016-8-24
 
  - Fix [#42](https://github.com/MadLittleMods/postcss-css-variables/issues/42) where `opts.preserve` was not working inside at-rules
-    - Thanks you to [@muftiev](github.com/muftiev) for the [contribution](https://github.com/MadLittleMods/postcss-css-variables/pull/43)
+    - Thank you to [@muftiev](github.com/muftiev) for the [contribution](https://github.com/MadLittleMods/postcss-css-variables/pull/43)
 
 
 # v0.5.1 - 2015-10-24