Add Python version modularity in venv scripts

[charlesbvll]

What does this implement/fix? Explain your changes.

The dev/venv-create.sh and baselines/dev/venv-create.sh scripts didn't work with versions of Python that were not 3.7.12. Now the scripts will also install the right Python version through pyenv install $version before creating the virtual environment.

By default the Python version used is 3.7.12, but an other version can be given as argument of the script, for example :

./dev/create-venv.sh 3.8.10 will create the virtual environment flower-3.8.10 using Python 3.8.10.

Note that the dev/venv-delete.sh and baselines/dev/venv-delete.sh will work in the same fashion. By default, it will delete the virtual environment that is using Python 3.7.12 but an argument can be given to delete a virtual environment that uses another version. If we continue with our previous example,

./dev/delete-venv.sh 3.8.10 will delete the virtual environment flower-3.8.10 that we created with the previous command.

Any other comments?

This page of the docs would need to be updated accordingly (even though the changes shouldn't break the explained steps) .

[tanertopal]

@charlesbvll I like it! I just suggested adding two comments so it's easier to understand what's happening. We can merge it after you apply the suggested changes. Feel free to rewrite the comments, though.

Resolved !