Describe the bug
The OpenAIPromptExecutionSettings object is not available.

To Reproduce
Steps to reproduce the behavior:

1. Install Microsoft.SemanticKernel from nuget (defaults to 1.0.0-beta8)
2. Copy code into IDE
3. See error

Expected behavior
The README code should execute with minimal changes

Platform

• OS: Windows
• IDE: Visual Studio
• Language: C#
• Source: 1.0.0-beta8

Additional context
Pull request attached