chore(deps): update xamarin & androidx to 1.6.0 (#4340)

This PR contains the following updates:

| Package | Change |
[Age](https://docs.renovatebot.com/merge-confidence/) |
[Confidence](https://docs.renovatebot.com/merge-confidence/) |
|---|---|---|---|
| [Xamarin.AndroidX.Collection.Jvm](https://aka.ms/android-libraries)
([source](https://redirect.github.com/xamarin/AndroidX)) | `1.5.0.5` →
`1.6.0` |
![age](https://developer.mend.io/api/mc/badges/age/nuget/Xamarin.AndroidX.Collection.Jvm/1.6.0?slim=true)
|
![confidence](https://developer.mend.io/api/mc/badges/confidence/nuget/Xamarin.AndroidX.Collection.Jvm/1.5.0.5/1.6.0?slim=true)
|
| [Xamarin.AndroidX.Collection.Ktx](https://aka.ms/android-libraries)
([source](https://redirect.github.com/xamarin/AndroidX)) | `1.5.0.5` →
`1.6.0` |
![age](https://developer.mend.io/api/mc/badges/age/nuget/Xamarin.AndroidX.Collection.Ktx/1.6.0?slim=true)
|
![confidence](https://developer.mend.io/api/mc/badges/confidence/nuget/Xamarin.AndroidX.Collection.Ktx/1.5.0.5/1.6.0?slim=true)
|

---

### Configuration

📅 **Schedule**: (UTC)

- Branch creation
  - At any time (no schedule defined)
- Automerge
  - At any time (no schedule defined)

🚦 **Automerge**: Disabled by config. Please merge this manually once you
are satisfied.

♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the
rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about these
updates again.

---

- [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check
this box

---

This PR was generated by [Mend Renovate](https://mend.io/renovate/).
View the [repository job
log](https://developer.mend.io/github/reactiveui/ReactiveUI).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0My4xNDEuMyIsInVwZGF0ZWRJblZlciI6IjQzLjE0MS4zIiwidGFyZ2V0QnJhbmNoIjoibWFpbiIsImxhYmVscyI6WyJEZXBlbmRlbmN5IE1hbmFnZW1lbnQiXX0=-->

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

src/Directory.Packages.props

@@ -74,8 +74,8 @@
     <!-- Fragment/Collection/SavedState to match their latest constraints -->
     <PackageVersion Include="Xamarin.AndroidX.Fragment" Version="1.8.9.2" />
     <PackageVersion Include="Xamarin.AndroidX.Fragment.Ktx" Version="1.8.9.2" />
-    <PackageVersion Include="Xamarin.AndroidX.Collection.Jvm" Version="1.5.0.5" />
-    <PackageVersion Include="Xamarin.AndroidX.Collection.Ktx" Version="1.5.0.5" />
+    <PackageVersion Include="Xamarin.AndroidX.Collection.Jvm" Version="1.6.0" />
+    <PackageVersion Include="Xamarin.AndroidX.Collection.Ktx" Version="1.6.0" />
     <PackageVersion Include="Xamarin.AndroidX.SavedState" Version="1.4.0.2" />
     <PackageVersion Include="Xamarin.AndroidX.SavedState.SavedState.Ktx" Version="1.4.0.2" />
     <PackageVersion Include="Xamarin.AndroidX.Preference" Version="1.2.1.17" />