Auto merge of #80746 - ehuss:update-cargo, r=ehuss

Update cargo

12 commits in 75d5d8cffe3464631f82dcd3c470b78dc1dda8bb..329895f5b52a358e5d9ecb26215708b5cb31d906
2020-12-22 18:10:56 +0000 to 2021-01-06 00:01:52 +0000
- metadata: Supply local path for path dependencies (rust-lang/cargo#8994)
- Add support for Rust edition 2021. (rust-lang/cargo#8922)
- Stabilize -Zfeatures and -Zpackage-features. (rust-lang/cargo#8997)
- Small refactor, adding a list of all kinds to BuildContext (rust-lang/cargo#9046)
- Fix git http.proxy config setting. (rust-lang/cargo#8986)
- Clarify the help text of `--aggressive` and `--precise` of `update` (rust-lang/cargo#9031)
- Assert that tests are run in the crate directory (rust-lang/cargo#9037)
- Update mdbook (rust-lang/cargo#9044)
- Bump to 0.52.0, update changelog (rust-lang/cargo#9042)
- Fix redundant semicolon. (rust-lang/cargo#9033)
- Clarify fingerprint log messages (rust-lang/cargo#9026)
- Update credential docs for gnome-secret. (rust-lang/cargo#9013)

diff --cc Cargo.lock
Simple merge