Update README.md

Change pre-PSR-0 tag name

Author: sabberworm

README.md

@@ -489,7 +489,7 @@ To output the entire CSS document into a variable, just use `->__toString()`:
 
 ## Misc
 
-* Legacy Support: The latest pre-PSR-0 version of this project can be checked out as the `v0.9` tag.
+* Legacy Support: The latest pre-PSR-0 version of this project can be checked with the `0.9.0` tag.
 * Running Tests: To run all unit tests for this project, have `phpunit` installed, `cd` to the `tests` dir and run `phpunit --bootstrap bootstrap.php .`.
 
 ## License