update how to get latest release

[Seasawher]

resolve #26

This PR is tested at mk-exercise: https://github.com/Seasawher/mk-exercise

[Seasawher]

I have made a tool to sort semvar in Lean. see Seasawher/Semver.lean.

[Seasawher]

scripts/getLatest.ps1 has a following job:

1. download the list of all releases via gh command
2. create a file with content of step 1
3. download the binary of Seasawher/semver via gh command
4. run semver.exe to update lean-toolchain
5. remove temporary files

This is a bit compicated, so simplification may be required. If the process of sorting can be achieved as a PowerShell script, that might be better.

How do you think?

[kim-em]

I don't understand why an executables are involved. This should look like a Semver type, with appropriate functions to and from strings, and LE and LT instances.

[oliver-butterley]

Thanks @Seasawher for putting together a working version of this idea. I'm not completely comfortable with this solution, rather like you write in your own comment. We should aim for a much cleaner solution. I see two main possibilities:

• A lean based solution but using the already existing Semver type. Thanks @semorrison for pointing this out.
• Redo the entire action as javascript/node. This then allows the standard semver library to be used. I rather favour the second alternative and can do the overhaul as soon as I manage to get some spare time. It has various other benefits: javascript/node is essentially the native thing for gh actions, the code will be much more maintainable and better user feedback can be done in a manageable way (the gh toolkit adds substantially to the ease of this and the cleanliness of the code). As a script based action it is already a little ungainly, and being javascript will allow painless scaling of features.

[Seasawher]

Redo the entire action as javascript/node. This then allows the standard semver library to be used.

This sounds nice