Bump regex from 1.8.3 to 1.8.4

[dependabot]

Bumps regex from 1.8.3 to 1.8.4.

Changelog

Sourced from regex's changelog.

1.8.4 (2023-06-05)

This is a patch release that fixes a bug where (?-u:\B) was allowed in Unicode regexes, despite the fact that the current matching engines can report match offsets between the code units of a single UTF-8 encoded codepoint. That in turn means that match offsets that split a codepoint could be reported, which in turn results in panicking when one uses them to slice a &str.

This bug occurred in the transition to regex 1.8 because the underlying syntactical error that prevented this regex from compiling was intentionally removed. That's because (?-u:\B) will be permitted in Unicode regexes in regex 1.9, but the matching engines will guarantee to never report match offsets that split a codepoint. When the underlying syntactical error was removed, no code was added to ensure that (?-u:\B) didn't compile in the regex 1.8 transition release. This release, regex 1.8.4, adds that code such that Regex::new(r"(?-u:\B)") returns to the regex <1.8 behavior of not compiling. (A bytes::Regex can still of course compile it.)

Bug fixes:

• [BUG #1006](rust-lang/regex#1006): Fix a bug where (?-u:\B) was allowed in Unicode regexes, and in turn could lead to match offsets that split a codepoint in &str.

Commits

• 5a34a39 1.8.4
• 407f6d3 changelog: 1.8.4
• b2ca9c1 compile: make Regex::new(r"(?-u:\B)") fail again
• See full diff in compare view

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