Bump log4net from 1.2.10 to 2.0.10 in /Src/StackifyLib.log4net.v1_2_10

Bumps [log4net](https://github.com/apache/logging-log4net) from 1.2.10 to 2.0.10.
- [Release notes](https://github.com/apache/logging-log4net/releases)
- [Changelog](https://github.com/apache/logging-log4net/blob/master/ReleaseInstructions.txt)
- [Commits](apache/logging-log4net@rel/1.2.10...rel/2.0.10)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Src/StackifyLib.log4net.v1_2_10/packages.config

@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="log4net" version="1.2.10" targetFramework="net40" />
+  <package id="log4net" version="2.0.10" targetFramework="net40" />
 </packages>