Bump System.Net.Http.Json from 8.0.1 to 9.0.0 in /source

Bumps [System.Net.Http.Json](https://github.com/dotnet/runtime) from 8.0.1 to 9.0.0.
- [Release notes](https://github.com/dotnet/runtime/releases)
- [Commits](dotnet/runtime@v8.0.1...v9.0.0)

---
updated-dependencies:
- dependency-name: System.Net.Http.Json
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

source/Example/Example.csproj

@@ -10,7 +10,7 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="8.0.1" />
     <PackageReference Include="Microsoft.Extensions.Http" Version="8.0.1" />
-    <PackageReference Include="System.Net.Http.Json" Version="8.0.1" />
+    <PackageReference Include="System.Net.Http.Json" Version="9.0.0" />
   </ItemGroup>
 
   <ItemGroup>