fix: revert to python 3.11
Some python tools, such as checkov are not yet compatible with 3.12. This reverts to python 3.11.
Example failed pipeline: https://gitlab.com/gitlab-com/gl-infra/gitlab-dedicated/instrumentor/-/jobs/5443524840
Further reading: https://github.com/langchain-ai/langchain/issues/11479
Edited by Andrew Newdigate