Update the samples ef core package version to 6.0. (#1114)

samples/Sample.RabbitMQ.SqlServer/Sample.RabbitMQ.SqlServer.csproj

@@ -6,11 +6,11 @@
 
   <ItemGroup>
     <PackageReference Include="Dapper" Version="2.0.78" />
-    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="5.0.4">
+    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="6.0.0">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="5.0.4" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="6.0.0" />
   </ItemGroup>
  
   <ItemGroup>