Fix build issue when using dotnet 8.0.300

[omer-za]

dotnet/sdk#40445

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• Run the following to build the project and update samples:

  ./mvnw clean package 
  ./bin/generate-samples.sh ./bin/configs/*.yaml
  ./bin/utils/export_docs_generators.sh
  

  (For Windows users, please run the script in Git BASH)
  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
  These must match the expectations made by your contribution.
  You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*.
  IMPORTANT: Do NOT purge/delete any folders/files (e.g. tests) when regenerating the samples as manually written tests may be removed.
• File the PR against the correct branch: master (upcoming 7.1.0 minor release - breaking changes with fallbacks), 8.0.x (breaking changes without fallbacks)
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[omer-za]

@wing328 Can you please review and help me push it forward ?

[wing328]

thanks for the PR. i've filed #18720 based on your PR with updated samples.

all tests passed.

if no further feedback, I'll merge this PR later this week.

cc @devhl-labs

[omer-za]

Thanks @wing328 ! when is the next expected release ?

[wing328]

https://github.com/OpenAPITools/openapi-generator/milestones

you can use customized templates (e.g. -t via CLI) for the time being