print() is a function in Python 3

Signed-off-by: Christian Clauss <[email protected]>

Author: cclauss

README.md

@@ -58,7 +58,7 @@ You can stream logs:
 
 ```python
 >>> for line in container.logs(stream=True):
-...   print line.strip()
+...   print(line.strip())
 Reticulating spline 2...
 Reticulating spline 3...
 ...