install virtualenv for python3.6 for mapit
install virtualenv for python3.6 for mapit

Co-Authored-By: Chris Ashton <2f515dc6e91662ff11b619335287254716cfcb8f@users.noreply.github.com>

alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet