Moved Spanish translation to completed section.

Author: jwasham

README.md

@@ -11,10 +11,11 @@
 > *Best of luck to you!*
 
 Translations:
-- [中文版本](translations/README-cn.md)
-- [Tiếng Việt - Vietnamese](translations/README-vi.md)
-- translations in progress:
-    - [Español](https://github.com/jwasham/coding-interview-university/issues/80)
+    - [中文版本](translations/README-cn.md)
+    - [Tiếng Việt - Vietnamese](translations/README-vi.md)
+    - [Español](translations/README-es.md)
+
+Translations in progress:
     - [हिन्दी](https://github.com/jwasham/coding-interview-university/issues/81)
     - [עברית](https://github.com/jwasham/coding-interview-university/issues/82)
     - [Bahasa Indonesia](https://github.com/jwasham/coding-interview-university/issues/101)