Bump sqlfluff from 3.3.1 to 3.4.0 in /src

Bumps [sqlfluff](https://github.com/sqlfluff/sqlfluff) from 3.3.1 to 3.4.0.
- [Release notes](https://github.com/sqlfluff/sqlfluff/releases)
- [Changelog](https://github.com/sqlfluff/sqlfluff/blob/main/CHANGELOG.md)
- [Commits](sqlfluff/sqlfluff@3.3.1...3.4.0)

---
updated-dependencies:
- dependency-name: sqlfluff
  dependency-version: 3.4.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

src/requirements.txt

@@ -4,7 +4,7 @@ gunicorn==23.0.0
 pytest==8.3.5
 pytest-watch==4.2.0
 pytest-cov==6.1.1
-sqlfluff==3.3.1
+sqlfluff==3.4.0
 
 # sql/util/* dependencies
 pandas==2.2.3