Update to Serilog 4

Author: Numpsy

src/Serilog.Enrichers.Thread/Enrichers/ThreadIdEnricher.cs

@@ -43,7 +43,7 @@ public void Enrich(LogEvent logEvent, ILogEventPropertyFactory propertyFactory)
             var threadId = Environment.CurrentManagedThreadId;
 
             var last = _lastValue;
-            if (last == null || (int)((ScalarValue)last.Value).Value != threadId)
+            if (last is null || (int)((ScalarValue)last.Value).Value! != threadId)
                 // no need to synchronize threads on write - just some of them will win
                 _lastValue = last = new LogEventProperty(ThreadIdPropertyName, new ScalarValue(threadId));
 

src/Serilog.Enrichers.Thread/Enrichers/ThreadNameEnricher.cs

@@ -41,10 +41,10 @@ public class ThreadNameEnricher : ILogEventEnricher
         public void Enrich(LogEvent logEvent, ILogEventPropertyFactory propertyFactory) 
         {
             var threadName = Thread.CurrentThread.Name;
-            if (threadName != null) 
+            if (threadName is not null) 
             {
                 var last = _lastValue;
-                if (last == null || (string)((ScalarValue)last.Value).Value != threadName)
+                if (last is null || (string)((ScalarValue)last.Value).Value! != threadName)
                     // no need to synchronize threads on write - just some of them will win
                     _lastValue = last = new LogEventProperty(ThreadNamePropertyName, new ScalarValue(threadName));
 

src/Serilog.Enrichers.Thread/Serilog.Enrichers.Thread.csproj

@@ -27,7 +27,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Serilog" Version="2.9.0" />
+    <PackageReference Include="Serilog" Version="4.0.0" />
   </ItemGroup>
 
   <ItemGroup>