Fixes provisioning of a new VM.
Old versions like 2019.2.3 may be moved to an archive
and get an HTTP 404 error.
Relaxing the pinned version allows setup to find
newer patches, such as 2019.2.5.
More info:
752768b1ff/accepted/0022-old-releases.md
The new version of Salt ("3000") seems to have a number of bugs,
including not being able to handle "unless" checks, which the Tildes
states use frequently. Because of this, creating a new dev environment
currently doesn't work. This pins Salt to the previous stable version
for now.
Here's the relevant bug for "unless" specifically:
https://github.com/saltstack/salt/issues/56131
And the overall release notes:
https://docs.saltstack.com/en/latest/topics/releases/3000.html
Without setting any defaults, it seems to give 1024MB of memory and 2
CPUs. That low of memory can (and does) result in the VM swapping itself
to death when doing some things. I'm going to set a reasonable amount in
the Vagrantfile, and update the docs to explain how to raise/lower it if
necessary (and recommend a minimum).
