Correct previous change to include wrong targets

Previously the nuspec was changed to use the merge.targets which was incorrect.  That file gets merged into the template produced targets to generate Xamarin.Android.Support.Vector.Drawable.targets which is what needs to be packaged into the nuget.

Author: Redth

vector-drawable/nuget/Xamarin.Android.Support.Vector.Drawable.nuspec

@@ -22,7 +22,7 @@
   </metadata>
   <files>
     <file src="vector-drawable/buildtask/bin/Release/Xamarin.Android.Support.Tasks.VectorDrawable.dll" target="build/MonoAndroid70" />
-    <file src="vector-drawable/nuget/merge.targets" target="build/MonoAndroid70/Xamarin.Android.Support.Vector.Drawable.targets" />
+    <file src="vector-drawable/nuget/Xamarin.Android.Support.Vector.Drawable.targets" target="build/MonoAndroid70/Xamarin.Android.Support.Vector.Drawable.targets" />
 
     <file src="output/Xamarin.Android.Support.Vector.Drawable.dll" target="lib/MonoAndroid70" />
   </files>