Fixing readme.txt

Signed-off-by: Jason Myers <[email protected]>

Author: jasonamyers

README.txt

@@ -11,12 +11,7 @@ managing your development workflow, making it easier to work on more
 than one project at a time without introducing conflicts in their
 dependencies.
 
-**Warning:** The 4.x release includes some potentially incompatible
-changes for extensions from 3.x. The python modules for extensions are
-now *always* run with ``PWD=$WORKON_HOME`` (previously the value of
-PWD varied depending on the hook). The *shell* portion of any hook
-(anything sourced by the user's shell when the hook is run) is still
-run in the same place as before.
+**Warning:** The 5.x release requires virtualenv 20+
 
 ========
 Features