build(deps): update ReactiveUI.XamForms requirement in /samples (#399)

Updates the requirements on [ReactiveUI.XamForms](https://github.com/reactiveui/reactiveui) to permit the latest version.
- [Release notes](https://github.com/reactiveui/reactiveui/releases)
- [Commits](reactiveui/ReactiveUI@16.1.1...17.0.1)

---
updated-dependencies:
- dependency-name: ReactiveUI.XamForms
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

samples/LoginApp.Forms.Android/LoginApp.Forms.Android.csproj

@@ -56,7 +56,7 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="ReactiveUI.XamForms" Version="16.*" />
+    <PackageReference Include="ReactiveUI.XamForms" Version="17.*" />
   </ItemGroup>
   <ItemGroup>
     <Compile Include="MainActivity.cs" />

samples/LoginApp.Forms/LoginApp.Forms.csproj

@@ -10,7 +10,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="ReactiveUI.XamForms" Version="16.*" />
+    <PackageReference Include="ReactiveUI.XamForms" Version="17.*" />
   </ItemGroup>
 
   <ItemGroup>