build(deps): bump Xamarin.Forms from 5.0.0.2545 to 5.0.0.2578 in /src (#3515)

Bumps Xamarin.Forms from 5.0.0.2545 to 5.0.0.2578.

---
updated-dependencies:
- dependency-name: Xamarin.Forms
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

src/ReactiveUI.XamForms/ReactiveUI.XamForms.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="MSBuild.Sdk.Extras">
+<Project Sdk="MSBuild.Sdk.Extras">
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;net6.0;net7.0</TargetFrameworks>
     <PackageDescription>Contains the ReactiveUI platform specific extensions for Xamarin Forms</PackageDescription>
@@ -7,7 +7,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Xamarin.Forms" Version="5.0.0.2545" />
+    <PackageReference Include="Xamarin.Forms" Version="5.0.0.2578" />
   </ItemGroup>
 
   <ItemGroup>