Bump diff-cover from 7.5.0 to 7.7.0 in /dependencies/python (#4488)

Bumps [diff-cover](https://github.com/Bachmann1234/diff-cover) from 7.5.0 to 7.7.0.
- [Release notes](https://github.com/Bachmann1234/diff-cover/releases)
- [Changelog](https://github.com/Bachmann1234/diff_cover/blob/main/CHANGELOG)
- [Commits](https://github.com/Bachmann1234/diff-cover/compare/v7.5.0...v7.7.0)

---
updated-dependencies:
- dependency-name: diff-cover
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Zack Koppert <zkoppert@github.com>

dependencies/python/sqlfluff.txt

@@ -2,7 +2,7 @@ appdirs==1.4.4
 chardet==5.1.0
 click==8.1.3
 colorama==0.4.6
-diff-cover==7.5.0
+diff-cover==7.7.0
 exceptiongroup==1.1.2
 iniconfig==2.0.0
 Jinja2==3.1.2