Change version to 0.0.12-release to ensure it sorts after 0.0.12-dev.

versions.json

 {
   "obfs4proxy": {
-    "0.0.12": {
+    "0.0.12-release": {
       "repo_url": "https://git.torproject.org/pluggable-transports/obfs4.git",
       "revision": "a564bc3840bc788605e1a8155f4b95ce0d70c6db",
       "build_path": "obfs4proxy",