update dependencies

packages/py-viziphant/package.py

@@ -28,9 +28,9 @@ class PyViziphant(PythonPackage):
     depends_on('py-six@1.10.0:', type=('build', 'run'))
     depends_on('py-matplotlib@3.3.2:', type=('build', 'run'))
     depends_on('py-seaborn@0.9.0:', type=('build', 'run'))
-    depends_on('py-bokeh@3.0.0:', type=('build', 'run'), when="@0.4.0:")
+    depends_on('py-bokeh@2.4.3:', type=('build', 'run'), when="@0.4.0:")
     depends_on('py-holoviews@1.16.0:', type=('build', 'run'), when="@0.4.0:")
-    depends_on('py-networkx@3.0.0:', type=('build', 'run'), when="@0.4.0:")
+    depends_on('py-networkx@2.8.6:', type=('build', 'run'), when="@0.4.0:")
 
     depends_on("py-pytest", type=("test"), when="@0.3.0:")
     depends_on("py-elephant@0.9.0:+extras", type=("test"), when="@0.3.0:")