Mark ITemplateCache as experimental (#790)

Author: sebastienros

.editorconfig

@@ -92,6 +92,9 @@ csharp_prefer_system_threading_lock = true:suggestion
 # IDE0078: Use pattern matching
 dotnet_diagnostic.IDE0078.severity = silent
 
+# FLUID001: Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+dotnet_diagnostic.FLUID001.severity = none
+
 [*.{cs,vb}]
 #### Naming styles ####
 

Fluid/ITemplateCache.cs

@@ -1,8 +1,11 @@
+using System.Diagnostics.CodeAnalysis;
+
 namespace Fluid;
 
 /// <summary>
 /// Interface for caching parsed templates in memory.
 /// </summary>
+[Experimental("FLUID001")]
 public interface ITemplateCache
 {
     /// <summary>