Improve your ASP.NET Core API inner development loop by integrating liblab into MSBuild

Integrating liblab into MSBuild targets allows developers to improve their ASP.NET Core API inner development loop by generating not only an updated OpenAPI spec, but also a full SDK with every build. This is achieved by adding a custom target to the `.csproj` file, which runs the liblab CLI after the NSwag tool has generated the OpenAPI spec. The resulting flow enables developers to generate an SDK in 6+ languages for any API, and can be demonstrated using a sample project on GitHub.