Updated packages

Author: FlorianRappl

src/AngleSharp.Io.Tests/packages.config

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
   <package id="AngleSharp" version="0.9.6" targetFramework="net45" />
-  <package id="FluentAssertions" version="4.5.0" targetFramework="net45" />
-  <package id="NUnit" version="3.2.1" targetFramework="net45" />
-  <package id="NUnitTestAdapter" version="2.0.0" targetFramework="net46" />
+  <package id="FluentAssertions" version="4.12.0" targetFramework="net45" />
+  <package id="NUnit" version="3.4.1" targetFramework="net45" />
 </packages>