chore: declare requires-python<3.13 in pyproject (#8547)

* restrict to python<3.13

* try unpinning dulwich

* reintroduce dulwich pin

pyproject.toml

@@ -8,7 +8,7 @@ dynamic = ["version"]
 description = "LLM framework to build customizable, production-ready LLM applications. Connect components (models, vector DBs, file converters) to pipelines or agents that can interact with your data."
 readme = "README.md"
 license = "Apache-2.0"
-requires-python = ">=3.8"
+requires-python = ">=3.8,<3.13"
 authors = [{ name = "deepset.ai", email = "malte.pietsch@deepset.ai" }]
 keywords = [
   "BERT",