build(deps): bump Xamarin.AndroidX.AppCompat in /src

Bumps [Xamarin.AndroidX.AppCompat](https://github.com/xamarin/AndroidX) from 1.2.0.7 to 1.3.0.
- [Release notes](https://github.com/xamarin/AndroidX/releases)
- [Commits](https://github.com/xamarin/AndroidX/commits)

---
updated-dependencies:
- dependency-name: Xamarin.AndroidX.AppCompat
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

src/ReactiveUI.AndroidX/ReactiveUI.AndroidX.csproj

@@ -11,7 +11,7 @@
 
   <ItemGroup>
     <PackageReference Include="System.Runtime.Serialization.Primitives" Version="4.3.0" />
-    <PackageReference Include="Xamarin.AndroidX.AppCompat" Version="1.2.0.7" />
+    <PackageReference Include="Xamarin.AndroidX.AppCompat" Version="1.3.0" />
     <PackageReference Include="Xamarin.AndroidX.Fragment" Version="1.3.3" />
     <PackageReference Include="Xamarin.AndroidX.Preference" Version="1.1.1.8" />
     <PackageReference Include="Xamarin.AndroidX.RecyclerView" Version="1.2.0" />