Build against .NET 10 preview

[bkoelman]

Attempting to stay up-to-date with the upcoming changes for .NET 10, EF Core 10 and Microsoft.OpenAPI 2.0 (which Swashbuckle depends on).

The output of this PR is published to our private NuGet feed, so that users can give it a try.

QUALITY CHECKLIST

• [ ] Changes implemented in code
• [ ] Complies with our contributing guidelines
• [ ] Adapted tests
• [ ] Documentation updated

[codecov[bot]]

Codecov Report

:white_check_mark: All modified and coverable lines are covered by tests. :white_check_mark: Project coverage is 91.81%. Comparing base (ba3accf) to head (c87ed0a).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1710      +/-   ##
==========================================
- Coverage   92.80%   91.81%   -0.99%     
==========================================
  Files         437      370      -67     
  Lines       14831    12036    -2795     
  Branches     2392     2011     -381     
==========================================
- Hits        13764    11051    -2713     
+ Misses        654      617      -37     
+ Partials      413      368      -45     

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