Previously, the Windows installer was shipping Python 3.8.10, which was

the newest release in the 3.8 series at the time. We're now shipping

3.8.13.
This was chosen over Python 3.9 or 3.10 due to still being compatible

with Windows 7 systems. While we may want to drop Windows 7 soon, we

want to make sure we communicate that correctly before we do it.
There are no official Python 3.8.13 builds, so we've built our own

signed installer using their official process, hosted on S3. This has

been tested and verified to work. When we move to a newer release, we

can go back to consuming official installers.
There are some other fixes in here as well. We no longer block on MD5

verification, which could happen sometimes due to PowerShell looking for

more scripts on stdin. We also have better error handling for the

installation stage, and we output the path to the installer in case we

need to debug things.

Successfully built the installers. Verified they worked on a Windows

install without Python.