Reacting to System.Text.Encoding package version change

Author: pranavkm

src/Microsoft.AspNet.StaticFiles/project.json

@@ -21,7 +21,7 @@
         "System.Runtime": "4.0.20.0",
         "System.Runtime.Extensions": "4.0.10.0",
         "System.Runtime.InteropServices": "4.0.20.0",
-        "System.Text.Encoding": "4.0.20.0",
+        "System.Text.Encoding": "4.0.10.0",
         "System.Threading.Tasks": "4.0.10.0"
       }
     }