refactor(localtunnel): attach RequirePreview attribute to localtunnel

This closes #684.

There should be documentation on how to use webhooks until a stable solution for local urls is found

Author: buehler

examples/WebhookOperator/WebhookOperator.csproj

@@ -5,6 +5,7 @@
         <Nullable>enable</Nullable>
         <ImplicitUsings>enable</ImplicitUsings>
         <IsPackable>false</IsPackable>
+        <EnablePreviewFeatures>true</EnablePreviewFeatures>
     </PropertyGroup>
 
     <ItemGroup>

src/KubeOps.Operator.Web/Builder/OperatorBuilderExtensions.cs

@@ -1,4 +1,5 @@
 using System.Reflection;
+using System.Runtime.Versioning;
 
 using KubeOps.Abstractions.Builder;
 using KubeOps.Operator.Web.LocalTunnel;
@@ -37,6 +38,9 @@ public static class OperatorBuilderExtensions
     ///     ;
     /// </code>
     /// </example>
+    [RequiresPreviewFeatures(
+        "Localtunnel is sometimes unstable, use with caution. " +
+        "This API is in preview and may be removed in future versions if no stable alternative is found.")]
     public static IOperatorBuilder AddDevelopmentTunnel(
         this IOperatorBuilder builder,
         ushort port,

test/Directory.Build.props

@@ -5,6 +5,7 @@
         <Nullable>enable</Nullable>
         <IsPackable>false</IsPackable>
         <IsTestProject>true</IsTestProject>
+        <EnablePreviewFeatures>true</EnablePreviewFeatures>
     </PropertyGroup>
 
     <ItemGroup>