deps(deps): update litellm requirement

Updates the requirements on [litellm](https://github.com/BerriAI/litellm) to permit the latest version.
- [Release notes](https://github.com/BerriAI/litellm/releases)
- [Commits](BerriAI/litellm@litellm_1.81.13-dev...v1.87.0)

---
updated-dependencies:
- dependency-name: litellm
  dependency-version: 1.87.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

pyproject.toml

@@ -29,7 +29,7 @@ classifiers = [
 ]
 keywords = ["llm", "ai", "tournament", "evaluation", "decision-making", "litellm"]
 dependencies = [
-    "litellm>=1.77.1,<1.86.0",
+    "litellm>=1.77.1,<1.88.0",
     "pyyaml~=6.0",
     "colorama~=0.4.6",
     "httpx~=0.28.1",