fix: nullable must be handled

PacketMediator.Samples/Program.cs

@@ -0,0 +1,3 @@
+// Licensed to Timothy Schenk under the Apache 2.0 License.
+
+Console.WriteLine("Hello World!");

PacketMediator.Samples/Sample.cs

@@ -0,0 +1,8 @@
+// Licensed to Timothy Schenk under the Apache 2.0 License.
+
+namespace PacketMediator.Samples;
+
+public class Sample
+{
+    
+}

RaiNote.PacketMediator/RaiNote.PacketMediator.csproj

@@ -20,6 +20,7 @@
     <PackageReadmeFile>README.md</PackageReadmeFile>
     <IncludeSymbols>true</IncludeSymbols>
     <SymbolPackageFormat>snupkg</SymbolPackageFormat>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
   </PropertyGroup>
 
   <ItemGroup>