Bump 1.3.0dev

Signed-off-by: Aanand Prasad <[email protected]>

compose/__init__.py

@@ -1,4 +1,4 @@
 from __future__ import unicode_literals
 from .service import Service  # noqa:flake8
 
-__version__ = '1.2.0'
+__version__ = '1.3.0dev'