Fix rustup download & installation on Windows

[lionel-faber]

When downloading the rustup-init binary for installation on Windows it should be named rustup-init.exe in order to be executable on the runner. If not it fails with the following error:

Error: Unable to locate executable file: D:\a\_temp\27bbd22a-fb15-4983-b256-c980efbc05b8. Please verify either the file path exists or the file can be found within a directory specified by the PATH environment variable. Also verify the file has a valid extension for an executable file.

The issue is locally reproducible on master through this test (run on Windows):

import { RustUp } from '../src/commands/rustup';

test('RustupGetOrInstall', async () => {
    process.env.RUNNER_TEMP = '_temp';
    await jest.setTimeout(10000);
    await expect(RustUp.getOrInstall()).resolves.toBeDefined();
});

I believe the issue hasn't turned up so far since the GitHub-hosted Windows runners already have rustup installed so RustUp.getOrInstall() has never hit the install phase. I came across this while using a self-hosted runner. See this failed build that first uninstalls rustup before running actions-rs/toolchain

The test is long-running (depending on internet speed - for the download) so a shaky network causes it to fail. So I didn't add it to the suite.

Credits to @TingluoHuang for pointing me in the right direction.

[lionel-faber]

I updated actions-rs/toolchain with this branch and you can see the passing step

[jedbrown]

I also encountered this error when the previous step wrote the PATH to $GITHUB_ENV.

echo PATH="/c/Program Files/Microsoft MPI/Bin${PATH:+:${PATH}}" | tee -a $GITHUB_ENV

[mihirsamdarshi]

also waiting on this PR to be merged

[pinkforest]

Hey I've forked actions-rs/core to rinse-repeat/actions-rs-core - which we're now using at rustsec/audit-check

pls feel free to send the PR there thanks