update CrossPlatformLiveData.Android.nuspec

Author: jakdor

CrossPlatformLiveData.Android/CrossPlatformLiveData.Android.nuspec

@@ -17,7 +17,7 @@
 		<group targetFramework=".NETStandard2.0">
 			<dependency id="CrossPlatformLiveData" version="1.0.0" />
 		</group>
-		<group targetFramework="monoandroid81">
+		<group targetFramework="monoandroid90">
 			<dependency id="Xamarin.Android.Support.Fragment" version="28.0.0.1" />
 			<dependency id="Xamarin.Android.Support.v7.AppCompat" version="28.0.0.1" />
 		</group>