[release/8.0] Bump System.Text.Json

Bumps the runtime-dependencies group in /eng/dependabot/net8.0 with 1 update: [System.Text.Json](https://github.com/dotnet/runtime).


Updates `System.Text.Json` 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
  update-type: version-update:semver-patch
  dependency-group: runtime-dependencies
...

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

eng/dependabot/net8.0/Versions.props

@@ -12,6 +12,6 @@
     <!-- Microsoft.NETCore.App -->
     <MicrosoftNETCoreApp80Version>8.0.8</MicrosoftNETCoreApp80Version>
     <!-- System.Text.Json -->
-    <SystemTextJson80Version>8.0.4</SystemTextJson80Version>
+    <SystemTextJson80Version>8.0.5</SystemTextJson80Version>
   </PropertyGroup>
 </Project>