Bump Serilog version dependency

Author: bdovaz

src/Serilog.Extensions.Logging/Serilog.Extensions.Logging.csproj

@@ -27,7 +27,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Serilog" Version="2.8.0" />
+    <PackageReference Include="Serilog" Version="2.9.0" />
     <PackageReference Include="Microsoft.Extensions.Logging" Version="2.0.0" />
   </ItemGroup>