Create a `make venv` target, that creates a virtual environment and installs the dependency in that venv. `make time` and all the related targets are changed to use the virtual environment python. Automerge-Triggered-By: @pablogsal
Co-authored-by: Guido van Rossum <guido@python.org> Co-authored-by: Lysandros Nikolaou <lisandrosnik@gmail.com>