Mark csharp template as deprecated

In favour of dotnet8-csharp

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

template/csharp/template.yml

@@ -1,11 +1,7 @@
 language: csharp
 fprocess: dotnet ./root.dll
 welcome_message: |
- You have created a C# function using the Classic OpenFaaS Template.
+ This template is deprecated and will be removed in a future
+ release.
 
- To include third-party dependencies edit your .csproj file or install
- Nuget packages with VSCode.
-
- For high-throughput applications, we recommend using the csharp-kestrel
- or csharp-httprequest templates available in the OpenFaaS template
- store.
+ Use dotnet8-csharp instead.