Auto merge of #71138 - ehuss:update-cargo, r=ehuss

Update cargo

12 commits in 390e8f245ef2cd7ac698b8a76abf029f9abcab0d..74e3a7d5b756d7c0e94399fc29fcd154e792c22a
2020-04-07 17:46:45 +0000 to 2020-04-13 20:41:52 +0000
- Update dependencies to support illumos target (rust-lang/cargo#8093)
- Whitelist another known spurious curl error (rust-lang/cargo#8102)
- Fix nightly test matching rustc "warning" output. (rust-lang/cargo#8098)
- Update default for codegen-units. (rust-lang/cargo#8096)
- Fix freshness when linking is interrupted. (rust-lang/cargo#8087)
- Add `cargo tree` command. (rust-lang/cargo#8062)
- Add "build-finished" JSON message. (rust-lang/cargo#8069)
- Extend -Zpackage-features with more capabilities. (rust-lang/cargo#8074)
- Disallow invalid dependency names through crate renaming (rust-lang/cargo#8090)
- Use the same filename hash for pre-release channels. (rust-lang/cargo#8073)
- Index the commands section (rust-lang/cargo#8081)
- Upgrade to mdBook v0.3.7 (rust-lang/cargo#8083)