Bump regex from 2026.1.15 to 2026.6.28

Bumps [regex](https://github.com/mrabarnett/mrab-regex) from 2026.1.15 to 2026.6.28.
- [Changelog](https://github.com/mrabarnett/mrab-regex/blob/hg/changelog.txt)
- [Commits](mrabarnett/mrab-regex@2026.1.15...2026.6.28)

---
updated-dependencies:
- dependency-name: regex
  dependency-version: 2026.6.28
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

requirements-lock.txt

@@ -58,7 +58,7 @@ pytz==2026.2
     # via pandas
 pyyaml==6.0.3
     # via sqlfluff
-regex==2026.1.15
+regex==2026.6.28
     # via sqlfluff
 six==1.17.0
     # via python-dateutil