release/create content-type default to "application/octet-stream"

[razum2um]

for example, see release done via web ui: https://api.github.com/repos/DomainDrivenArchitecture/smeagol/releases/14283686
one asset has content_type: "application/x-java-archive"

another release done via hub: https://api.github.com/repos/DomainDrivenArchitecture/smeagol/releases/14536031
has content_type: "application/octet-stream"

I think there should be a way to specify this (maybe via cmd flag)

[mislav]

Good catch!

https://github.com/github/hub/blob/d89b5c6fe4180ebab8c12f9c7d663ce7621164c8/github/http.go#L311

I'm open to ideas

[razum2um]

@mislav we can also detect it using https://github.com/gabriel-vasile/mimetype (since https://github.com/h2non/filetype has issues with container type, e.g. jar) - what do you prefer?