build(deps): Bump ReactiveMarbles.ObservableEvents.SourceGenerator (#768)

Bumps [ReactiveMarbles.ObservableEvents.SourceGenerator](https://github.com/reactivemarbles/ObservableEvents) from 1.2.3 to 1.3.1.
- [Release notes](https://github.com/reactivemarbles/ObservableEvents/releases)
- [Commits](reactivemarbles/ObservableEvents@1.2.3...1.3.1)

---
updated-dependencies:
- dependency-name: ReactiveMarbles.ObservableEvents.SourceGenerator
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

winforms/demo2/WinForms.Reactive.Client.Tests/WinForms.Reactive.Client.Tests.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFramework>net7.0-windows10.0.17763.0</TargetFramework>
@@ -9,7 +9,7 @@
 
   <ItemGroup>
 	  <PackageReference Include="FluentAssertions" Version="6.12.0" />
-	  <PackageReference Include="ReactiveMarbles.ObservableEvents.SourceGenerator" Version="1.2.3">
+	  <PackageReference Include="ReactiveMarbles.ObservableEvents.SourceGenerator" Version="1.3.1">
 		  <PrivateAssets>all</PrivateAssets>
 		  <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
 	  </PackageReference>

winforms/demo2/WinForms.Reactive.Client/WinForms.Reactive.Client.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <OutputType>WinExe</OutputType>
@@ -11,7 +11,7 @@
 
 	<ItemGroup>
 		<PackageReference Include="Microsoft.Extensions.Hosting" Version="7.0.1" />
-		<PackageReference Include="ReactiveMarbles.ObservableEvents.SourceGenerator" Version="1.2.3">
+		<PackageReference Include="ReactiveMarbles.ObservableEvents.SourceGenerator" Version="1.3.1">
 			<PrivateAssets>all</PrivateAssets>
 			<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
 		</PackageReference>