Update __init__.py (#785)

Author: majorgreys

ddtrace/__init__.py

@@ -4,7 +4,7 @@
 from .tracer import Tracer
 from .settings import config
 
-__version__ = '0.19.0'
+__version__ = '0.20.0'
 
 # a global tracer instance with integration settings
 tracer = Tracer()