update packages version

Author: hephaex

python-tensorflow/requirements.20.03.txt

@@ -66,7 +66,7 @@ google-auth==1.11.2
 google-auth-oauthlib==0.4.1
 google-images-download==2.8.0
 google-pasta==0.1.8
-graphviz==0.8.4
+graphviz==0.13.2
 grpcio==1.27.2
 h5py==2.10.0
 HeapDict==1.0.1