Bump the dependencies group in /src/Moneybird.Net with 1 update

Bumps the dependencies group in /src/Moneybird.Net with 1 update: [System.Text.Json](https://github.com/dotnet/runtime).


Updates `System.Text.Json` from 8.0.2 to 8.0.3
- [Release notes](https://github.com/dotnet/runtime/releases)
- [Commits](dotnet/runtime@v8.0.2...v8.0.3)

---
updated-dependencies:
- dependency-name: System.Text.Json
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: dependencies
...

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

src/Moneybird.Net/Moneybird.Net.csproj

@@ -18,7 +18,7 @@
 
     <ItemGroup>
       <PackageReference Include="Macross.Json.Extensions" Version="3.0.0" />
-      <PackageReference Include="System.Text.Json" Version="8.0.2" />
+      <PackageReference Include="System.Text.Json" Version="8.0.3" />
     </ItemGroup>
 
     <ItemGroup>