neuron: bump to 9.0.a15

[jorblancoa]

No description provided.

[bbpbuildbot]

Thank you for your pull request!

Should you want to clear the PR build directory after failures, please use this pipeline. Before running the cleanup pipeline, please ensure that any PR building pipelines have been cancelled or finished running.

[WeinaJi]

LGTM. Maybe @pramodk or @alkino can confirm this version.

[bbpbuildbot]

To test your PR, use the following on BlueBrain5:

unset MODULEPATH
. /gpfs/bbp.cscs.ch/ssd/apps/bsd/pulls/2268/config/modules.sh
module load unstable

Please test the following updated modules:

• neurodamus-hippocampus/1.8-3.0a1-2.8.1
• neurodamus-mousify/1.6-3.0a1-2.8.1
• neurodamus-neocortex-multiscale/1.13-3.0a1-2.8.1
• neurodamus-neocortex-plasticity/1.13-3.0a1-2.8.1
• neurodamus-neocortex/1.13-3.0a1-2.8.1
• neurodamus-thalamus/1.6-3.0a1-2.8.1
• neuron/9.0.a15
• psp-validation/0.5.0
• py-bbp-workflow/3.1.53
• py-bluepyemodel/0.0.64
• py-bluepyemodelnexus/0.0.7
• py-bluepymm/0.8.7
• py-bluepyopt/1.14.4
• py-minis-validation/0.0.5
• py-morph-tool/2.9.1
• py-multiscale-run/0.4
• py-region-grower/1.2.9
• py-synthesis-workflow/1.1.0