chore: spack cherry-pick: podio: depends_on py-graphviz

This PR will install py-graphviz so as to make sure podio-vis works.

spack-environment/packages.yaml

@@ -159,7 +159,7 @@ packages:
     - '@0.20'
   jana2:
     require:
-    - '@2.1.2'
+    - '@git.d8fe7adb523432d9e9b7e8fd98b97f7c646053a7'
     - -ipo +podio +root +zmq
   juggler:
     require: