Bump System.Text.Json in /src/NodaTime.Serialization.SystemTextJson

Bumps [System.Text.Json](https://github.com/dotnet/runtime) from 8.0.4 to 8.0.5.
- [Release notes](https://github.com/dotnet/runtime/releases)
- [Commits](dotnet/runtime@v8.0.4...v8.0.5)

---
updated-dependencies:
- dependency-name: System.Text.Json
  dependency-type: direct:production
...

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

Author: dependabot[bot]

src/NodaTime.Serialization.SystemTextJson/NodaTime.Serialization.SystemTextJson.csproj

@@ -19,6 +19,6 @@
 
   <ItemGroup>
     <PackageReference Include="NodaTime" Version="[3.0.0,4.0.0)" />
-    <PackageReference Include="System.Text.Json" Version="8.0.4" Condition="'$(TargetFramework)' == 'netstandard2.0'" />
+    <PackageReference Include="System.Text.Json" Version="8.0.5" Condition="'$(TargetFramework)' == 'netstandard2.0'" />
   </ItemGroup>
 </Project>