Fix #65 Formatting issue in README

[vidhula17]

Why are these changes needed?

The README file had a formatting issue in the Multi-agent conversations section, which made it difficult to read and understand.

Related issue number

Closes #65

Checks

• I've included any doc changes needed for https://microsoft.github.io/autogen/. See https://microsoft.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.

[sonichi]

Thanks. There is another PR #69 for the same issue.
Could you help with that PR, or work on a different PR? Or revisit this PR if #69 doesn't resolve the issue?

[yiranwu0]

Closing this PR with the merge of a similar PR #69.