Rollup rustup output in a CI log group

[epage]

Current output for an MSRV job looks like:

Run cargo hack check --all-targets --rust-version --workspace --ignore-private
info: skipped running on private package `cargo-test-macro`
info: skipped running on private package `cargo-test-support`
info: skipped running on private package `mdman`
info: skipped running on private package `resolver-tests`
info: skipped running on private package `semver-check`
info: skipped running on private package `xtask-build-man`
info: skipped running on private package `xtask-bump-check`
info: skipped running on private package `xtask-stale-label`
info: skipped running on private package `benchsuite`
info: skipped running on private package `capture`
info: syncing channel updates for '1.70-x86_64-unknown-linux-gnu'
info: latest update on 2023-06-01, rust version 1.70.0 (90c541806 2023-05-31)
info: downloading component 'cargo'
info: downloading component 'rust-std'
info: downloading component 'rustc'
info: installing component 'cargo'
info: installing component 'rust-std'
info: installing component 'rustc'

  1.70-x86_64-unknown-linux-gnu installed - rustc 1.70.0 (90c541806 2023-05-31)

running `rustup run 1.70 cargo check --all-targets` on cargo-platform (1/10)
running `rustup run 1.70 cargo check --all-targets` on home (2/10)
running `rustup run 1.70 cargo check --all-targets` on cargo-credential (3/10)
running `rustup run 1.70 cargo check --all-targets` on cargo-credential-1password (4/10)
info: syncing channel updates for '1.72-x86_64-unknown-linux-gnu'
info: latest update on 2023-08-24, rust version 1.72.0 (5680fa18f 2023-08-23)
info: downloading component 'cargo'
info: downloading component 'rust-std'
info: downloading component 'rustc'
info: installing component 'cargo'
info: installing component 'rust-std'
info: installing component 'rustc'

  1.72-x86_64-unknown-linux-gnu installed - rustc 1.72.0 (5680fa18f 2023-08-23)

running `rustup run 1.72 cargo check --all-targets` on cargo-util (5/10)
running `rustup run 1.72 cargo check --all-targets` on crates-io (6/10)
running `rustup run 1.72 cargo check --all-targets` on cargo (7/10)
running `rustup run 1.72 cargo check --all-targets` on cargo-credential-libsecret (8/10)
running `rustup run 1.72 cargo check --all-targets` on cargo-credential-macos-keychain (9/10)
running `rustup run 1.72 cargo check --all-targets` on cargo-credential-wincred (10/10)

It'd be nice to instead be

Run cargo hack check --all-targets --rust-version --workspace --ignore-private
info: skipped running on private package `cargo-test-macro`
info: skipped running on private package `cargo-test-support`
info: skipped running on private package `mdman`
info: skipped running on private package `resolver-tests`
info: skipped running on private package `semver-check`
info: skipped running on private package `xtask-build-man`
info: skipped running on private package `xtask-bump-check`
info: skipped running on private package `xtask-stale-label`
info: skipped running on private package `benchsuite`
info: skipped running on private package `capture`
rustup toolchain install '1.70-x86_64-unknown-linux-gnu'
running `rustup run 1.70 cargo check --all-targets` on cargo-platform (1/10)
running `rustup run 1.70 cargo check --all-targets` on home (2/10)
running `rustup run 1.70 cargo check --all-targets` on cargo-credential (3/10)
running `rustup run 1.70 cargo check --all-targets` on cargo-credential-1password (4/10)
rustup toolchain install '1.72-x86_64-unknown-linux-gnu'
running `rustup run 1.72 cargo check --all-targets` on cargo-util (5/10)
running `rustup run 1.72 cargo check --all-targets` on crates-io (6/10)
running `rustup run 1.72 cargo check --all-targets` on cargo (7/10)
running `rustup run 1.72 cargo check --all-targets` on cargo-credential-libsecret (8/10)
running `rustup run 1.72 cargo check --all-targets` on cargo-credential-macos-keychain (9/10)
running `rustup run 1.72 cargo check --all-targets` on cargo-credential-wincred (10/10)

See rust-lang/cargo#12654