Stacked Git 2.0.0-rc.1

This first 2.0 release candidate brings a new look to the online help thanks to updating to clap 4.0. Further compatibility improvements with sparse checkouts and multiple worktrees comes from the update to git2 0.15.0. And several changes were made to support patch names starting with '-'.

Added

• Added --annotate flag to stg email send.
• Added -p/--patch option to stg show as alternative way to select patch ranges (#216).
• Added -n/--name option to stg new as alternative way to specify new patch name (#216).

Changed

• Update git2 to 0.15.0, which may further help compatibility with sparse checkouts and multiple worktrees (#195).
• Update to clap 4.0, which changes the help formatting and coloring.
• Update other dependencies to latest versions in Cargo.lock.
• No longer depend on lazy_static crate.
• Use std::thread::scope instead of custom mechanism. This brings the total number of uses of unsafe in StGit to zero.
• Minimum rustc requirement is set to 1.63.0.
• The '$' sigil used for committed patches is now yellow instead of white.
• Patch names beginning with a hyphen '-' may be disambiguated from command line options by escaping the leading '-' with a backslash.
• stg email format and stg email send now use -G/--git-opts to pass additional options to git format-patch and git send-email.
• Patch name arguments to stg email format and stg email-send can now be placed after a -- separator (#216).
• Update top-level usage help for stg.

Fixed

• Various errors that may occur when executing a stack transaction are now handled more robustly such that the changes from the transaction are rolled-back so that the stack, repository, and worktree are all in a consistent state (#205).
• The stg uncommit -h usage indentation is repaired.
• The stg float usage now shows the two distinct usage modes.
• stg squash --name allows patch names with leading '-'.
• stg diff --range allows patch names and ranges with leading '-'.
• Fix some pre-indented paragraphs in help/about strings.
• Zsh completion for stg edit incorrectly included -O/--diff-opts.
• Zsh completion for stg files incorrectly included -O/--diff-opts.