Update README.md

Author: belforte

README.md

@@ -2,9 +2,11 @@
 
 Command Line client for the CRABServer REST interface.
 
-BRANCHES as of June 10 2021
+BRANCHES as of August 30 2021
 * master
   * for porting to python3, no WMCore etc.
 * v3.210607patch
   * forked from tag v3.210607 which is now in production
-  * to push important, needed patched to production but aim is to keep stable while working on py3 
+  * to push important, needed patched to production but aim is to keep stable while working on py3
+* py2only
+   * created from v3.210607patch plus a couple fixes. Stable release which only works with python2 CMSSW (i.e. < CMSSW_12)