fix(ruby): Detect content-type in form-data file upload using faraday (#17851)

[dvacca-onfido]

Differently than other generators (e.g. Python), Ruby generator using Faraday as HTTP client is not able to provide correct content type when file is uploaded as part of multipart/form-data payload.

Expected: image/jpeg (if JPEG image was uploaded)
Received: application/octet-stream

I'd kindly ask also for guidance in choosing target branch, since the content-type previously provided was clearly wrong, but still this change might possibly break some integrations.

Fixes issue #17851.

@cliffano @zlx @autopp

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[wing328]

CI tests failed: https://app.circleci.com/pipelines/github/OpenAPITools/openapi-generator/27900/workflows/148b8cfa-8bca-42f5-8940-e9d6d0cf2520/jobs/88739

can you please take a look when you've time?

[dvacca-onfido]

Might it help rebasing my change and generating the examples again?

@@ -1 +1 @@
-7.3.0-SNAPSHOT
\ No newline at end of file
+7.4.0-SNAPSHOT
Perform git status

https://github.com/OpenAPITools/openapi-generator/actions/runs/7887425395/job/21525679113?pr=17853

[wing328]

Might it help rebasing my change and generating the examples again?

please merge/pull the latest master into your branch and regenerate the samples again?

PM via slack if you need further assistance

[wing328]

lgtm. thanks for the PR.