Fix for z_shift

[torbjone]

The z_shift that is used when the MoI method is used to calculate ECoG signals was broken in RecMEAElectrode class (see LFPy/LFPy#280).

[espenhgn]

Hi @torbjone ; I think you have to allow Actions in your repository's Settings column on github

[espenhgn]

I'll try and fix these workflow problems - there's more to it: https://docs.github.com/en/free-pro-team@latest/actions/reference/events-that-trigger-workflows#pull-request-events-for-forked-repositories

[espenhgn]

@torbjone , can you please merge upstream changes from master? I've put coveralls testing in a separate step such that the Python application actions should run. Coveralls will most likely not work on your end. Please check the output of the Lintly flake8 checks for formatting issues if that also fails.

[espenhgn]

@torbjone; I fixed the linting issues. Do you plan on pushing anything else?
I don't see anything in the PR that would break anything, so that's all swell.

Just ignore the coveralls error, can merge anyway.