Check user's version of Odin executables

[gvrooyen]

Since Odin has monthly and nightly builds, it might be worthwhile to have a script that checks if you have Odin installed and whether it's outdated. If so, it can download the correct version from GitHub. (@BNAndras)

The test.yml GitHub Action is configured to test the solution against a very specific Odin version (down to the commit hash), and this will also be the version against which Exercism users' solutions will be tested. Possible ways in which we can help contributors to test against the same version are:

1. Add a fetch-odin script that can fetch, build, and install the reference version of the compiler.
2. Let the fetch-odin --check-version / fetch-odin -c script compare the installed version with the reference version, and indicate whether an update is needed.
3. Let run-tests.sh give an INFO message if the currently installed Odin version is newer than the reference, and a WARNING if it is older.

[glennj]

I'm not sure I understand this issue. The user is supposed to have fetch-odin and run-tests.sh on their local machine? How are they supposed to acquire that? It could be downloaded into the exercise directory when the user does an exercism download -e $exercise. I personally am not keen to write the powershell version to run on windows.

What we currently have, an installation document is common to a lot of tracks: don't repeat what's already written on the language home, and note the current version that is used on our side.

[rmonnet]

Odin is nearly stable but listening to Ginger Bill there may still be some minor changes to the compiler (like the latest version disable literals for dynamic arrays) and to the standard library. We don't use that much of the standard library in the exercises so this should not be an issue.

For a student who is a beginner, he/she is most likely using the UI interface (I personally like to use the UI interface unless I got a very difficult exercise which I need to debug) and if they do, they are using the version we provide with the Test Runner. No problem there.

If the student had a very old version of the compiler, or if the Odin team introduced a breaking change (which they seems to indicate they wouldn't) then the worse that will happen is that the student will get a compiler error message. They would have to be using the CLI interface for that to happen and most likely have experience installing the Odin compiler (download, unzip, put on your path) so we can reasonably expect they would be able to pinpoint the problem.

I concur with @glennj that this is not a to priority right now. I would suggest that we close the issue. Any objection?