added note about phpcas changes from 1.2.x to 1.3.x

README

@@ -13,7 +13,8 @@ This plugin has been tested and works with the following:
  - RHEL (specifically, Oracle Enterprise Linux) 6.1-6.2 x64 - DEBIAN Squeeze 2.6.26 x64
  - JASIG CAS 3.3.2, 3.4.11, 3.4.14 (http://www.jasig.org/cas)
  - pam_cas (https://sourcesup.cru.fr/frs/?group_id=213, Pam_cas-2.0.11-esup-2.0.5.tar.gz)
- - phpCAS 1.2.2 (php-pear-CAS from EPEL)
+ - phpCAS 1.3.x
+   - There was a function signature change between 1.2.x and 1.3.x! Please use 1.3.x
  - up-imapproxy 1.2.7 (http://www.imapproxy.org)
  - Dovecot 2.0.13 (http://dovecot.org)