update latest python 2 in pipenv-version step
update latest python 2 in pipenv-version step

ad-m/heroku-buildpack-python,heroku/heroku-buildpack-python,skilljar/heroku-buildpack-python,benmurden/heroku-buildpack-python-ember,benmurden/heroku-buildpack-python-ember,Scalingo/python-buildpack,AltSchool/heroku-buildpack-python,Scalingo/python-buildpack,ad-m/heroku-buildpack-python,benjaminfox/heroku-buildpack-python-geoip,heroku/heroku-buildpack-python,benjaminfox/heroku-buildpack-python-geoip,AltSchool/heroku-buildpack-python