Bump System.Text.Json from 7.0.2 to 7.0.3 (#2099)

Bumps [System.Text.Json](https://github.com/dotnet/runtime) from 7.0.2 to 7.0.3.
- [Release notes](https://github.com/dotnet/runtime/releases)
- [Commits](dotnet/runtime@v7.0.2...v7.0.3)

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

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

src/RestSharp/RestSharp.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
     <PropertyGroup>
         <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
     </PropertyGroup>