Bump MemoryPack from 1.21.1 to 1.21.3

Bumps [MemoryPack](https://github.com/Cysharp/MemoryPack) from 1.21.1 to 1.21.3.
- [Release notes](https://github.com/Cysharp/MemoryPack/releases)
- [Commits](Cysharp/MemoryPack@1.21.1...1.21.3)

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

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Flow.Launcher.Infrastructure/Flow.Launcher.Infrastructure.csproj

@@ -54,7 +54,7 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="MemoryPack" Version="1.21.1" />
+    <PackageReference Include="MemoryPack" Version="1.21.3" />
     <PackageReference Include="Microsoft.VisualStudio.Threading" Version="17.10.48" />
     <PackageReference Include="NLog" Version="4.7.10" />
     <PackageReference Include="PropertyChanged.Fody" Version="3.4.0" />