[pick.py] changed checking for int to include int64 (#5978)
[pick.py] changed checking for int to include int64 (#5978)

* changed checking for int to include int64

* Update pick.py

* added explicit type casting to int

larsoner/mne-python,adykstra/mne-python,kambysese/mne-python,pravsripad/mne-python,Eric89GXL/mne-python,rkmaddox/mne-python,bloyl/mne-python,Teekuningas/mne-python,wmvanvliet/mne-python,mne-tools/mne-python,kingjr/mne-python,larsoner/mne-python,kingjr/mne-python,rkmaddox/mne-python,adykstra/mne-python,olafhauk/mne-python,larsoner/mne-python,mne-tools/mne-python,pravsripad/mne-python,mne-tools/mne-python,cjayb/mne-python,drammock/mne-python,drammock/mne-python,Teekuningas/mne-python,cjayb/mne-python,bloyl/mne-python,olafhauk/mne-python,Eric89GXL/mne-python,pravsripad/mne-python,olafhauk/mne-python,kingjr/mne-python,drammock/mne-python,Teekuningas/mne-python,kambysese/mne-python,wmvanvliet/mne-python,wmvanvliet/mne-python