Bump ReactiveMarbles.ObservableEvents.SourceGenerator

Bumps [ReactiveMarbles.ObservableEvents.SourceGenerator](https://github.com/reactivemarbles/ObservableEvents) from 1.1.4 to 1.2.3.
- [Release notes](https://github.com/reactivemarbles/ObservableEvents/releases)
- [Commits](https://github.com/reactivemarbles/ObservableEvents/compare/1.1.4...1.2.3)

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

Signed-off-by: dependabot[bot] <[email protected]>

ReactiveExample/ReactiveExample.csproj

@@ -13,7 +13,7 @@
   <ItemGroup>
     <PackageReference Include="ReactiveUI.Fody" Version="18.3.1" />
     <PackageReference Include="ReactiveUI" Version="18.3.1" />
-    <PackageReference Include="ReactiveMarbles.ObservableEvents.SourceGenerator" Version="1.1.4" PrivateAssets="all" />
+    <PackageReference Include="ReactiveMarbles.ObservableEvents.SourceGenerator" Version="1.2.3" PrivateAssets="all" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Terminal.Gui\Terminal.Gui.csproj" />