Renamed basic authentication function in sttp client

[aneksamun]

Fixed #8395 replacing withCredentials with basic.
Please see more details in official sttp client documentation
https://sttp.softwaremill.com/en/latest/requests/authentication.html.
Thanks.

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[aneksamun]

CircleCI build unrelated error:

[ERROR] Failed to execute goal on project petstore-okhttp-gson: Could not resolve dependencies for project org.openapitools:petstore-okhttp-gson:jar:1.0.0: Failed to collect dependencies at com.squareup.okhttp3:okhttp:jar:3.14.7: Failed to read artifact descriptor for com.squareup.okhttp3:okhttp:jar:3.14.7: Could not transfer artifact com.squareup.okhttp3:okhttp:pom:3.14.7 from/to central (https://repo.maven.apache.org/maven2): Connection reset -> [Help 1]

[wing328]

Thanks for the PR but your commit (as shown in the Commits tab) is not linked to your Github account, which means this PR won't count as your contribution in https://github.com/OpenAPITools/openapi-generator/graphs/contributors.

Let me know if you need help fixing it.

Ref: https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-can-i-update-commits-that-are-not-linked-to-my-github-account

[aneksamun]

Thanks for the PR but your commit (as shown in the Commits tab) is not linked to your Github account, which means this PR won't count as your contribution in https://github.com/OpenAPITools/openapi-generator/graphs/contributors.

Let me know if you need help fixing it.

Ref: https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-can-i-update-commits-that-are-not-linked-to-my-github-account

@wing328 Thanks for pointing this out. I've done changes as requested.