Bump ReactiveProperty from 8.2.0 to 9.1.2 (MessagePack-CSharp#1592)

Bumps [ReactiveProperty](https://github.com/runceel/ReactiveProperty) from 8.2.0 to 9.1.2.
- [Release notes](https://github.com/runceel/ReactiveProperty/releases)
- [Changelog](https://github.com/runceel/ReactiveProperty/blob/main/ReleaseNote-ja.md)
- [Commits](runceel/ReactiveProperty@8.2.0...9.1.2)

---
updated-dependencies:
- dependency-name: ReactiveProperty
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Directory.Packages.props

@@ -45,7 +45,7 @@
     <PackageVersion Include="NUnit3TestAdapter" Version="4.3.1" />
     <PackageVersion Include="protobuf-net" Version="3.1.25" />
     <PackageVersion Include="RandomFixtureKit" Version="1.0.1" />
-    <PackageVersion Include="ReactiveProperty" Version="8.2.0" />
+    <PackageVersion Include="ReactiveProperty" Version="9.1.2" />
     <PackageVersion Include="Sigil" version="5.0.0" />
     <PackageVersion Include="SpanJson" Version="4.0.0" />
     <PackageVersion Include="System.CodeDom" Version="7.0.0" />