Update Serilog dependency to 3.1.1

Author: nblumhardt

src/Serilog.Sinks.Console/Serilog.Sinks.Console.csproj

@@ -39,7 +39,7 @@
     </PropertyGroup>
 
     <ItemGroup>
-        <PackageReference Include="Serilog" Version="3.1.0-*" />
+        <PackageReference Include="Serilog" Version="3.1.1" />
         <PackageReference Include="Nullable" Version="1.3.0" PrivateAssets="all" />
     </ItemGroup>