Rollup merge of rust-lang#82490 - ehuss:update-cargo, r=ehuss

Update cargo

11 commits in bf5a5d5e5d3ae842a63bfce6d070dfd438cf6070..572e201536dc2e4920346e28037b63c0f4d88b3c
2021-02-18 15:49:14 +0000 to 2021-02-24 16:51:20 +0000
- Pass the error message format to rustdoc (rust-lang/cargo#9128)
- Fix test target_in_environment_contains_lower_case (rust-lang/cargo#9203)
- Fix hang on broken stderr. (rust-lang/cargo#9201)
- Make it more clear which module is being tested when running cargo test (rust-lang/cargo#9195)
- Updates to edition handling. (rust-lang/cargo#9184)
- Add --cfg and --rustc-cfg flags to output compiler configuration (rust-lang/cargo#9002)
- Run rustdoc doctests relative to the workspace (rust-lang/cargo#9105)
- Add support for [env] section in .cargo/config.toml (rust-lang/cargo#9175)
- Add schema field and `features2` to the index. (rust-lang/cargo#9161)
- Document the default location where cargo install emitting build artifacts (rust-lang/cargo#9189)
- Do not exit prematurely if anything failed installing. (rust-lang/cargo#9185)

Author: Dylan-DPC