Required by newest versions of clap and clap_lex.

    error: package `clap_lex v0.7.0` cannot be built because it requires rustc 1.74 or
    newer, while the currently active rustc version is 1.70.0
    Either upgrade to rustc 1.74 or newer, or use
    cargo update -p clap_lex@0.7.0 --precise ver
    where `ver` is the latest version of `clap_lex` supporting rustc 1.70.0

rust-lang/rust-clippy#12257

    warning: current MSRV (Minimum Supported Rust Version) is `1.31.0` but this item is stable since `1.57.0`
     --> tests/fst/mod.rs:5:44
      |
    5 |     fst::Set::from(fst::raw::Fst::new(data.as_slice()).unwrap())
      |                                            ^^^^^^^^^^
      |
      = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#incompatible_msrv
      = note: `-W clippy::incompatible-msrv` implied by `-W clippy::all`
      = help: to override `-W clippy::all` add `#[allow(clippy::incompatible_msrv)]`

    warning: current MSRV (Minimum Supported Rust Version) is `1.31.0` but this item is stable since `1.57.0`
      --> tests/fst/mod.rs:10:44
       |
    10 |     fst::Set::from(fst::raw::Fst::new(data.as_slice()).unwrap())
       |                                            ^^^^^^^^^^
       |
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#incompatible_msrv

    warning: current MSRV (Minimum Supported Rust Version) is `1.31.0` but this item is stable since `1.32.0`
      --> tests/compare.rs:46:48
       |
    46 |             xid_start_fst.contains((ch as u32).to_be_bytes()),
       |                                                ^^^^^^^^^^^^^
       |
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#incompatible_msrv

    warning: current MSRV (Minimum Supported Rust Version) is `1.31.0` but this item is stable since `1.32.0`
      --> tests/compare.rs:51:51
       |
    51 |             xid_continue_fst.contains((ch as u32).to_be_bytes()),
       |                                                   ^^^^^^^^^^^^^
       |
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#incompatible_msrv

    warning: current MSRV (Minimum Supported Rust Version) is `1.31.0` but this item is stable since `1.32.0`
      --> benches/xid.rs:88:44
       |
    88 |                 let ch_bytes = (ch as u32).to_be_bytes();
       |                                            ^^^^^^^^^^^^^
       |
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#incompatible_msrv

Something is screwed up with this and it is producing nondeterministic
outputs that I am not sure how to interpret.

    unicode-ident-diagram
    ================
    Name                          Project  Compat   Latest   Kind    Platform
    ----                          -------  ------   ------   ----    --------
    arbitrary                     0.4.7    1.3.2    1.3.2    Normal  ---
    arbitrary                     0.4.7    1.3.2    1.3.2    Normal  cfg(fuzzing)
    bitstream-io                  1.10.0   2.2.0    2.2.0    Normal  ---
    built                         0.5.2    0.7.1    0.7.1    Build   ---
    bumpalo                       3.15.4   Removed  Removed  Normal  ---
    cargo-lock                    8.0.3    Removed  Removed  Normal  ---
    cfg-if                        1.0.0    Removed  Removed  Normal  ---
    form_urlencoded               1.2.1    Removed  Removed  Normal  ---
    idna                          0.5.0    Removed  Removed  Normal  ---
    itertools                     0.10.5   0.12.1   0.12.1   Normal  ---
    libfuzzer-sys                 0.3.5    0.4.7    0.4.7    Normal  cfg(fuzzing)
    log                           0.4.21   Removed  Removed  Normal  ---
    num-derive                    0.3.3    0.4.2    0.4.2    Normal  ---
    once_cell                     1.19.0   Removed  Removed  Normal  ---
    percent-encoding              2.3.1    Removed  Removed  Normal  ---
    proc-macro2                   1.0.78   Removed  Removed  Normal  ---
    quote                         1.0.35   Removed  Removed  Normal  ---
    rav1e                         0.6.6    0.7.1    0.7.1    Normal  cfg(target = "wasm32-unknown-unknown")
    rust_hawktracer               0.7.0    Removed  Removed  Normal  ---
    rust_hawktracer_normal_macro  0.4.1    Removed  Removed  Normal  ---
    rust_hawktracer_proc_macro    0.4.1    Removed  Removed  Normal  ---
    rustc_version                 0.4.0    Removed  Removed  Build   ---
    semver                        1.0.22   Removed  Removed  Normal  ---
    serde                         1.0.197  Removed  Removed  Normal  ---
    serde_derive                  1.0.197  Removed  Removed  Normal  ---
    syn                           1.0.109  2.0.52   2.0.52   Normal  ---
    syn                           2.0.52   Removed  Removed  Normal  ---
    tinyvec                       1.6.0    Removed  Removed  Normal  ---
    tinyvec_macros                0.1.1    Removed  Removed  Normal  ---
    toml                          0.5.11   Removed  Removed  Normal  ---
    unicode-bidi                  0.3.15   Removed  Removed  Normal  ---
    unicode-ident                 1.0.12   Removed  Removed  Normal  ---
    unicode-normalization         0.1.23   Removed  Removed  Normal  ---
    url                           2.5.0    Removed  Removed  Normal  ---
    wasm-bindgen                  0.2.92   Removed  Removed  Normal  ---
    wasm-bindgen-backend          0.2.92   Removed  Removed  Normal  ---
    wasm-bindgen-macro            0.2.92   Removed  Removed  Normal  ---
    wasm-bindgen-macro-support    0.2.92   Removed  Removed  Normal  ---
    wasm-bindgen-shared           0.2.92   Removed  Removed  Normal  ---

See kbknapp/cargo-outdated#389. The bug has been
masked by kornelski/cavif-rs@d157737.

This reverts commit 2944bc6.

Debugging a recent cargo-outdated bug, it would have been nice not to
wonder whether a rustc version change in GitHub's runner image was a
contributing factor.

Update to Unicode 16.0.0