Update log4net to 2.0.10 for CVE-2018-1285.

Author: bgrainger

src/MySqlConnector.Logging.log4net/MySqlConnector.Logging.log4net.csproj

@@ -11,7 +11,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="log4net" Version="2.0.8" />
+    <PackageReference Include="log4net" Version="2.0.10" />
   </ItemGroup>
 
   <ItemGroup>