Cannot install different patch versions of the same major.minor version.

[acksmaggart]

I thought I had tested this before, but apparently if you have a major.minor version already installed and then try to install a newer patch version of that same major.minor version on windows only the most recently installed version (or maybe the highest version?) will work. For example, if you have already run Install-Python 3.7.2 and then you run Install-Python 3.7.3 the python executable in your 3.7.2 installation directory will be removed and only python 3.7.3 will work. This isn't a huge deal, but it does mean that the way this module thinks about managing python installations should probably change.

Specifically, instead of asking users to specify the major.minor.patch version when installing python and creating virtual environments they should only be asked to specify a major.minor version. Under the new paradigm Install-Python will install the latest patch version of the specified major.minor version and New-PythonVirtualEnvironment will use whatever patch version is installed for the specified major.minor version. Then the patch version can then be updated as new versions are released and the virtual environments will effectively be updated as well, since they just contain symbolic links. (I still need to test this to be sure.)

[acksmaggart]

It looks like before python 3.7.2 on windows, python -m venv copied the python.exe binary into the virtual environment. Meaning, of course, that you could trash the original install and the venv would still work, assuming you didn't depend on any system packages. Starting with 3.7.2 python -m venv uses symlinks, meaning that removing the original python.exe binary will break the venv.

See https://docs.python.org/3/library/venv.html

[acksmaggart]

It looks like running python -m venv --symlinks works to use symlinks instead of copying the binary, at least for python 3.6. So in addition to trimming down the version specifications to major.minor we will also have to change the the New-PythonVirtualEnvironment command to use the --symlinks flag so we can upgrade behind the scenes.

[acksmaggart]

Fixed in PR #23, version 2.0.0. The API change is detailed in the README.