chore(deps): update haystack-ai requirement in /integrations/cohere

Updates the requirements on [haystack-ai](https://github.com/deepset-ai/haystack) to permit the latest version.
- [Release notes](https://github.com/deepset-ai/haystack/releases)
- [Commits](deepset-ai/haystack@v2.23.0...v2.29.0)

---
updated-dependencies:
- dependency-name: haystack-ai
  dependency-version: 2.29.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

integrations/cohere/pyproject.toml

@@ -23,7 +23,7 @@ classifiers = [
   "Programming Language :: Python :: Implementation :: CPython",
   "Programming Language :: Python :: Implementation :: PyPy",
 ]
-dependencies = ["haystack-ai>=2.23.0", "cohere>=5.17.0", "pydantic>=2.12.0"]
+dependencies = ["haystack-ai>=2.29.0", "cohere>=5.17.0", "pydantic>=2.12.0"]
 
 [project.urls]
 Documentation = "https://github.com/deepset-ai/haystack-core-integrations/tree/main/integrations/cohere#readme"