`win-rustup` fetch task broken due to new version of rustup-init being released

[ahal]

Example: https://firefox-ci-tc.services.mozilla.com/tasks/UrNqpR6tRkixSHMeGdl7NA

I believe this is happening because the Rust community overwrote that task's URL with a newer binary at: https://static.rust-lang.org/rustup/dist/x86_64-pc-windows-msvc/rustup-init.exe

I'm seeing this in my PR because my PR happens to touch a file that causes this task to get re-built. But this failure will happen for everyone once the task expires.

The simple fix is to update the hash and size to the new values, though we'll run into the same error down the road whenever another release of rustup-init is made. The better fix would be to try and pin to a specific version of rustup-init, but I'm not sure if those are readily available anywhere or not.

┆Issue is synchronized with this Jira Bug