pydrive2: bump to 1.7.3

Author: efiop

setup.py

@@ -15,7 +15,7 @@
 
 setup(
     name="PyDrive2",
-    version="1.7.2",
+    version="1.7.3",
     author="JunYoung Gwak",
     author_email="jgwak@dreamylab.com",
     maintainer="DVC team",