Improve the `self update` command to account for the new installer#4084

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sdispater merged 2 commits intomasterfrom

improve-self-update

May 21, 2021

Commits on May 18, 2021

Ensure we don't pick up Poetry's virtualenv as the system env
sdispater
committed

Commits on May 21, 2021

Improve `self update` following the introduction of install-poetry.py
sdispater
committed