Indicate required Bash version

Author: aik099

README.md

@@ -817,7 +817,7 @@ Displays help for a command.
 ## Installation
 
 1. download [stable/svn-buddy.phar](http://svn-buddy-updater.herokuapp.com/download/stable/svn-buddy.phar) (stable release) or [snapshot/svn-buddy.phar](http://svn-buddy-updater.herokuapp.com/download/snapshot/svn-buddy.phar) (snapshot release)
-2. setup auto-completion by placing `eval $(/path/to/svn-buddy.phar _completion --generate-hook -p svn-buddy.phar)` in `~/.bashrc`
+2. setup auto-completion by placing `eval $(/path/to/svn-buddy.phar _completion --generate-hook -p svn-buddy.phar)` in `~/.bashrc` (Bash v4.0+ required)
 
 ## Requirements