bump LFPy-2.2.6 -> 2.3

Closes #22 (closed)

merged

mentioned in commit f8ab029d

Hi @ehagen, the updated LFPy Spack package was built successfully:

https://gitlab.ebrains.eu/technical-coordination/project-internal/devops/platform/ebrains-spack-builds/-/jobs/35157

You please need to validate that it's working as expected in the integration environment of the Lab in the "EBRAINS-test" kernel.

If everything is OK, the new package will be deployed to production with the weekly experimental release tomorrow.