Bump GraphQL.SystemTextJson from 7.3.0 to 7.3.1 (#114)

Bumps [GraphQL.SystemTextJson](https://github.com/graphql-dotnet/graphql-dotnet) from 7.3.0 to 7.3.1.
- [Release notes](https://github.com/graphql-dotnet/graphql-dotnet/releases)
- [Commits](graphql-dotnet/graphql-dotnet@7.3.0...7.3.1)

---
updated-dependencies:
- dependency-name: GraphQL.SystemTextJson
  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>

Author: dependabot[bot]

GraphQLNetExample/GraphQLNetExample.csproj

@@ -11,7 +11,7 @@
     <PackageReference Include="GraphQL.MicrosoftDI" Version="7.3.1" />
     <PackageReference Include="GraphQL.Server.Transports.AspNetCore" Version="7.3.0" />
     <PackageReference Include="GraphQL.Server.Ui.Altair" Version="7.3.0" />
-    <PackageReference Include="GraphQL.SystemTextJson" Version="7.3.0" />
+    <PackageReference Include="GraphQL.SystemTextJson" Version="7.3.1" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="7.0.4">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>