update NESTML and ODE-toolbox version in spack package list

packages/py-nestml/package.py

@@ -22,8 +22,7 @@ class PyNestml(PythonPackage):
     version('5.3.0', sha256='8de543d7d3a166cd4d6a0d536a2d4e769513bbf8d7aeaf64458e9d9c21fe546e', expand=False)
     version('5.2.0', sha256='acb703bf9c7f70304bd5d547dccd6a6a219f8acb298a6412df779b808241eb14', expand=False)
 
-    depends_on('python@3.8:', when='@:5.3', type=('build', 'run'))
-    depends_on('python@3.9:', when='@6.0.0:', type=('build', 'run'))
+    depends_on('python@3.8:', type=('build', 'run'))
     depends_on('py-pip', type='build')
     depends_on('py-numpy', type=('build', 'run'))
     depends_on('py-scipy', type=('build', 'run'))

packages/py-odetoolbox/package.py

@@ -21,7 +21,6 @@ class PyOdetoolbox(PythonPackage):
     depends_on('py-scipy', type=('build', 'run'))
     depends_on('py-numpy@1.8.2:', type=('build', 'run'))
     depends_on('py-cython', type=('build', 'run'))
-    depends_on('py-graphviz', type=('build', 'run'))
     depends_on('py-matplotlib', type=('build', 'run'))
     depends_on('py-setuptools', type=('build', 'run'))
     depends_on('py-pytest', type='test')