crowdin: Don't autodetect default branch

* This can easily lead to failures so add branch as an argument

Change-Id: Id29b4c65c551e490ee7206de22cff337ba7b8d95
diff --git a/README.mkdn b/README.mkdn
index 7a51aeb..101ea78 100644
--- a/README.mkdn
+++ b/README.mkdn
@@ -26,7 +26,7 @@
 Edit crowdin/config_cm.yaml to set the api key & your current CyanogenMod path.
 Execute:
 
-    ./crowdin_sync.py --username your_gerrit_username [--no-download|--no-upload]
+    ./crowdin_sync.py --username your_gerrit_username --branch cm_version [--no-download|--no-upload]
 
 Bugs
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