Update docker-py version in requirements to 1.7.2

Signed-off-by: Joffrey F <[email protected]>

requirements.txt

@@ -1,6 +1,6 @@
 PyYAML==3.11
 cached-property==1.2.0
-docker-py==1.7.1
+docker-py==1.7.2
 dockerpty==0.4.1
 docopt==0.6.1
 enum34==1.0.4