Update the version number on the repo launcher

The repo launcher version needs to be updated so some users can take
advantage of the more robust version number parsing.

Change-Id: Ibcd8036363311528db82db2b252357ffd21eb59b

repo

@@ -20,7 +20,7 @@ REPO_REV = 'stable'
 # limitations under the License.
 
 # increment this whenever we make important changes to this script
-VERSION = (1, 20)
+VERSION = (1, 21)
 
 # increment this if the MAINTAINER_KEYS block is modified
 KEYRING_VERSION = (1, 2)