rustc-ap-rustc_cratesio_shim 306.0.0

Automatically published version of the package `rustc_cratesio_shim` in the rust-lang/rust repository from commit a2fb99bc17527798aeeef1d7ccc61811a9362131 The publishing script for this crate lives at: https://github.com/alexcrichton/rustc-auto-publish