fix version number

Author: JohnMount

README.md

@@ -12,7 +12,7 @@ in a statistically sound manner.
 Install `vtreat` with either of:
 
   * `pip install vtreat`
-  * `pip install https://github.com/WinVector/pyvtreat/raw/master/pkg/dist/vtreat-0.2.7.tar.gz`
+  * `pip install https://github.com/WinVector/pyvtreat/raw/master/pkg/dist/vtreat-0.2.8.tar.gz`
 
 # Details