Update Cargo

Unblocking PRs:
- rust-lang/cargo#5535 - Ignore <tab> in libtest output. (unblocks rust-lang#50387)
- rust-lang/cargo#5537 - Remove -Zno-trans test. (unblocks rust-lang#50615)
- rust-lang/cargo#5540 - Fix tests when CARGO_TARGET_DIR is set. (unblocks self)

Regression fixes:
- rust-lang/cargo#5503 - cargo rustc broken for tests in project with bins
- rust-lang/cargo#5520 - (rust-lang#50640) shared proc-macro dependency built incorrectly

Changes:
- rust-lang/cargo#5527 - Point Source Replacement to the Overriding Dependencies section
- rust-lang/cargo#5533 - Detail how to run locally-built nightly cargo
- rust-lang/cargo#5522 - Add option to set user-agent
- rust-lang/cargo#5519 - NFC: fix a couple of typos, found by codespell.
- rust-lang/cargo#5513 - Fix `panic` for binaries built during tests.
- rust-lang/cargo#5512 - simplify build_requirements
- rust-lang/cargo#5301 - Add --build-plan for 'cargo build'
- rust-lang/cargo#5460 - Be more conservative about which files are linked to the output dir.
- rust-lang/cargo#5509 - Use the new stable
- rust-lang/cargo#5507 - Does not print seconds fraction with minutes
- rust-lang/cargo#5498 - Bump to 0.29.0
- rust-lang/cargo#5497 - Mention +nightly in ARCHITECTURE.md

Author: ehuss