update version - Githubissues

Why are these changes needed?

Update version for pre-release

[x] I've included any doc changes needed for https://autogen-ai.github.io/autogen/. See https://autogen-ai.github.io/autogen/docs/Contribute#documentation to build and test documentation locally.
[ ] I've added tests (if relevant) corresponding to the changes introduced in this PR.
[ ] I've made sure all auto checks have passed.