ci(nuget): make dotnet pack deterministic
ci(nuget): make dotnet pack deterministic

by adding the flag `-p:ContinuousIntegrationBuild=true`

Signed-off-by: Simon Eßlinger <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@esslinger.dev>

cloudevents/sdk-csharp,cloudevents/sdk-csharp