Update bindgen requirement from 0.66.0 to 0.68.1

[dependabot]

Updates the requirements on bindgen to permit the latest version.

Release notes

Sourced from bindgen's releases.

v0.68.1

Install bindgen-cli 0.68.1

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/rust-lang/rust-bindgen/releases/download/v0.68.1/bindgen-cli-installer.sh | sh

Install prebuilt binaries via powershell script

irm https://github.com/rust-lang/rust-bindgen/releases/download/v0.68.1/bindgen-cli-installer.ps1 | iex

Download bindgen-cli 0.68.1

File	Platform	Checksum
bindgen-cli-aarch64-apple-darwin.tar.xz	macOS Apple Silicon	checksum
bindgen-cli-x86_64-apple-darwin.tar.xz	macOS Intel	checksum
bindgen-cli-x86_64-unknown-linux-gnu.tar.xz	Linux x64	checksum

Changelog

Sourced from bindgen's changelog.

0.68.1

Fixed

• Fixed errors on the windows artifact build process.

0.68.0

Added

• The system ABI is now supported as an option for the --override-abi flag.
• The allowlist_item method and the --allowlist-item flag have been included to filter items regardless or their kind.
• Include installers as release artifacts on Github.

Changed

• The Clone implementation for _BindgenUnionField has been changed to pass the incorrect_clone_impl_on_copy_type Clippy lint.
• The c_unwind ABI can be used without a feature gate for any Rust target version equal to or greater than 1.71. This comes as a result of the ABI being stabilised (in Rust 1.71).
• Formatting changes when using prettyplease as a formatter due to a new prettyplease version.
• Avoid generating invalid CStr constants when using the --generate-cstr option.

Removed

• The extra_assert and extra_assert_eq macros are no longer exported.

Fixed

• Bindgen no longer panics when parsing an objective-C header that includes a Rust keyword that cannot be a raw identifier, such as: self, crate, super or Self.

0.67.0

This version was skipped due to some problems on the release workflow.

0.66.1

Removed

• Revert source order sorting (#2543) due to correctness regressions #2558.

0.66.0

Added

• Added the --generate-cstr CLI flag to generate string constants as &CStr instead of &[u8]. (Requires Rust 1.59 or higher.)
• Added the --generate-shell-completions CLI flag to generate completions for different shells.
• The --wrap-static-fns option can now wrap va_list functions as variadic functions with the experimental ParseCallbacks::wrap_as_variadic_fn method.
• Add target mappings for riscv32imc and riscv32imac.
• Add the ParseCallbacks::field_visibility method to modify field visibility.

... (truncated)

Commits

• 8d75a02 chore: Release
• a21e60b Release preparation for v0.68.1 (#2627)
• ebcf0bc chore: Release
• 59102e9 chore: Release
• f623bfb Don't release anything by default (#2623)
• 073fa62 test cli and lib msrv separately (#2625)
• b52377a Update CHANGELOG.md (#2622)
• 1d74af3 Don't delete the lockfile on the msrv workflow (#2621)
• ef2fb79 make search less surprising (#2613)
• ea3f8a7 there been editors not affilicated with Servo (#2615)
• Additional commits viewable in compare view

You can trigger a rebase of this PR by commenting @dependabot rebase.

---

Dependabot commands and options

You can trigger Dependabot actions by commenting on this PR:

• @dependabot rebase will rebase this PR
• @dependabot recreate will recreate this PR, overwriting any edits that have been made to it
• @dependabot merge will merge this PR after your CI passes on it
• @dependabot squash and merge will squash and merge this PR after your CI passes on it
• @dependabot cancel merge will cancel a previously requested merge and block automerging
• @dependabot reopen will reopen this PR if it is closed
• @dependabot close will close this PR and stop Dependabot recreating it. You can achieve the same result by closing it manually
• @dependabot show <dependency name> ignore conditions will show all of the ignore conditions of the specified dependency
• @dependabot ignore this major version will close this PR and stop Dependabot creating any more for this major version (unless you reopen the PR or upgrade to it yourself)
• @dependabot ignore this minor version will close this PR and stop Dependabot creating any more for this minor version (unless you reopen the PR or upgrade to it yourself)
• @dependabot ignore this dependency will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself)

Note
Automatic rebases have been disabled on this pull request as it has been open for over 30 days.