rustc-ap-rustc_cratesio_shim 520.0.0

Automatically published version of the package `rustc_cratesio_shim` in the rust-lang/rust repository from commit 4393768faa104b9879c601feee71eb0207dc4fe1 The publishing script for this crate lives at: https://github.com/alexcrichton/rustc-auto-publish