To prevent unbounded size growth, we want to delete older nightly and beta
manifests from master branch regularly. Users of old nightly and beta
toolchains can still access from the `before/` tags, but these tags will
not receive patch updates anymore. Currently cut-off can only be
deployed manually.
Stable versions are not affected and are all kept currently.
In nightly 2022-02-02, aarch64-apple-darwin's rust-docs actually points
to x86_64-apple-darwin's artifact URL. Most tier 2 targets'
rust-docs also forward to -unknown-linux-gnu with the same arch.
Not sure why they do so, but URL forwarding is implemented now.
