Merge branch 'fix_pynn-brainscales' into 'master'

Fix concretization error

See merge request akarmas/ebrains-spack-builds!13

packages/meta-brainscales/package.py

@@ -49,7 +49,7 @@ class MetaBrainscales(Package):
     depends_on('py-matplotlib')
     depends_on('py-nose')
     depends_on('py-numpy')
-    depends_on('py-pybind11')
+    depends_on('py-pybind11@2.6.0:2.6.999') # workaround concretization error (py-scipy doesn't like 2.7)
     depends_on('py-pybind11-stubgen')
     depends_on('py-pycodestyle')
     depends_on('py-pyelftools')