neuron: bump to 9.0.a15 (#2268)

Author: jorblancoa

bluebrain/repo-patches/packages/neuron/package.py

@@ -14,6 +14,7 @@ class Neuron(BuiltinNeuron):
 
     # BBP specific version
     version("develop", branch="master")
+    version("9.0.a15", commit="f64b609")
     version("9.0.a14", commit="bd9426d9")
     version("9.0.a13", commit="3bbdd8da")
     version("9.0.a5", commit="522c866")