housekeeping: Update Sample to AndroidX

Sample/SextantSample.Android/Resources/layout/Tabbar.axml

@@ -1,11 +1,12 @@
 <?xml version="1.0" encoding="utf-8"?>
-<android.support.design.widget.TabLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<android.support.design.widget.TabLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     android:id="@+id/sliding_tabs"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:background="?attr/colorPrimary"
-    android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
+    android:theme="@style/ThemeOverlay.MaterialComponents.ActionBar"
     app:tabIndicatorColor="@android:color/white"
     app:tabGravity="fill"
     app:tabMode="fixed" />

Sample/SextantSample.Android/SextantSample.Android.csproj

@@ -68,15 +68,16 @@
   <ItemGroup>
     <PackageReference Include="System.Reactive" Version="5.0.*" />
     <PackageReference Include="System.Threading.Tasks.Extensions" Version="4.5.4" />
-    <PackageReference Include="Xamarin.Android.Support.Design" Version="28.0.0.3" />
-    <PackageReference Include="Xamarin.Android.Support.v7.AppCompat" Version="28.0.0.3" />
-    <PackageReference Include="Xamarin.Android.Support.v4" Version="28.0.0.3" />
-    <PackageReference Include="Xamarin.Android.Support.v7.CardView" Version="28.0.0.3" />
-    <PackageReference Include="Xamarin.Android.Support.v7.MediaRouter" Version="28.0.0.3" />
+    <PackageReference Include="Xamarin.Google.Android.Material" Version="1.3.0.1" />
+    <PackageReference Include="Xamarin.AndroidX.AppCompat" Version="1.2.0.7" />
+    <PackageReference Include="Xamarin.AndroidX.Legacy.Support.V4" Version="1.0.0.7" />
+    <PackageReference Include="Xamarin.AndroidX.CardView" Version="1.0.0.8" />
+    <PackageReference Include="Xamarin.AndroidX.MediaRouter" Version="1.2.2.1" />
     <PackageReference Include="ReactiveUI.XamForms" Version="13.*" />
     <PackageReference Include="Xamarin.AndroidX.MediaRouter" Version="1.2.2.1" />
-    <PackageReference Include="Xamarin.AndroidX.Palette" Version="1.0.0.7" />    
-    <PackageReference Include="Xamarin.Forms" Version="5.0.*" />    
+    <PackageReference Include="Xamarin.AndroidX.Palette" Version="1.0.0.7" />
+    <PackageReference Include="Xamarin.Forms" Version="5.0.*" />
+    <PackageReference Include="Xamarin.AndroidX.Migration" Version="1.0.8" />
   </ItemGroup>
   <ItemGroup>
     <Compile Include="MainActivity.cs" />
@@ -124,4 +125,4 @@
     </ProjectReference>
   </ItemGroup>
   <Import Project="$(MSBuildExtensionsPath)\Xamarin\Android\Xamarin.Android.CSharp.targets" />
-</Project>
+</Project>