Tags for older releases

[JasmineLowen]

It would be nice to refer to older releases of rust by simply specifying a tag instead of search manually for the hash of the last commit that still has the mentioned older version of rust.

I propose just tagging the last commit of each rust release with it's version so that people can easily jump back in time.

What do you think?

[JasmineLowen]

E.g.

c7c6909

would be the last commit for 1.90.0 so it would get tagged that way.

I'm also open for opening issues for reminders whenever that happens :)

[eureka-cpu]

I wonder if this is necessary since you can just use the fromToolchainFile already or create a toolchain with the version you want? I'm not opposed to it, I'm sure it would help some people but we would probably want this to be automated if possible.

[JasmineLowen]

My main reason for this was to use something similar to #158

The upstream esp-rs/rust-build repo includes a custom rust-src and rust release. This is done to support extra compilation targets for some esp-chips. The repo itself is not always up to date. To avoid conflicts I'd like to pin both fenix and rust-build to have the same rust version.

Also fromToolchainFile is not really applicable here, since the workaround from the issue is hand-crafting a manifest and then uses fromManifest