chore(deps): update ruff requirement from >=0.15.11 to >=0.15.15

Updates the requirements on [ruff](https://github.com/astral-sh/ruff) to permit the latest version.
- [Release notes](https://github.com/astral-sh/ruff/releases)
- [Changelog](https://github.com/astral-sh/ruff/blob/main/CHANGELOG.md)
- [Commits](astral-sh/ruff@0.15.11...0.15.15)

---
updated-dependencies:
- dependency-name: ruff
  dependency-version: 0.15.15
  dependency-type: direct:production
...

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

Author: dependabot[bot]

requirements.txt

@@ -13,4 +13,4 @@ stix2==3.0.2
 stix2-validator==3.2.0
 
 # dev dependencies
-ruff>=0.15.11
+ruff>=0.15.15