Remove unnecessary dependency

Author: josesimoes

nanoFramework.System.Net.nuspec

@@ -21,7 +21,6 @@ This package requires a target with System.Net v$nativeVersion$ (checksum $check
     <dependencies>
       <dependency id="nanoFramework.CoreLibrary" version="1.17.11" />
       <dependency id="nanoFramework.Runtime.Events" version="1.11.39" />
-      <dependency id="nanoFramework.System.Text" version="1.3.42" />
       <dependency id="nanoFramework.System.Threading" version="1.1.52" />
       <dependency id="nanoFramework.System.IO.Streams" version="1.1.96" />
     </dependencies>
@@ -37,4 +36,4 @@ This package requires a target with System.Net v$nativeVersion$ (checksum $check
     <file src="assets\nf-logo.png" target="images" />
     <file src="LICENSE.md" target="" />
   </files>
-</package>
+</package>