fix: Fix NPC constraint for NPC.Get and fix csproj for latest rider

Author: MaxtorCoder

S1API/Entities/NPC.cs

@@ -592,7 +592,7 @@ public bool ConversationCanBeHidden
         /// </summary>
         /// <typeparam name="T">The NPC class to get the instance of.</typeparam>
         /// <returns></returns>
-        public static NPC? Get<T>() =>
+        public static NPC? Get<T>() where T : NPC =>
             All.FirstOrDefault(npc => npc.GetType() == typeof(T));
 
         #endregion

S1API/S1API.csproj

@@ -17,6 +17,7 @@
         <Platforms>AnyCPU</Platforms>
         <RootNamespace>S1API</RootNamespace>
         <GenerateDocumentationFile>true</GenerateDocumentationFile>
+        <LangVersion>latest</LangVersion>
     </PropertyGroup>
 
     <PropertyGroup Condition="'$(Configuration)' == 'MonoMelon' or '$(Configuration)' == 'MonoBepInEx'">