Update ctor dependency?

[bolinfest]

Apparently Cargo.toml currently specifies ctor = "0.1.26":

allocative/Cargo.toml

Line 13 in 85b773d

ctor = "0.1.26"

Today, the current version is 0.5.0:

https://crates.io/crates/ctor

[bolinfest]

@dtolnay @ndmitchell Assuming this is done, it would be great if Starlark were updated to use the newer version of this crate.