Implement optional io.Reader in AudioRequest (#303) (#265)

[mdarc]

This change adds an optional io.Reader to the AudioRequest structure. This addition makes this structure more versatile and allows you to use a different source other than an existing file from your filesystem. It also maintaining backwards compatibility.

I'd be glad to implement the same logic for the other Request types (FileRequest, ImageEditRequest, ImageVariRequest) in preferably subsequent PR's.

[codecov]

Codecov Report

Merging #331 (4b25634) into master (62eb4be) will increase coverage by 0.68%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #331      +/-   ##
==========================================
+ Coverage   92.36%   93.05%   +0.68%     
==========================================
  Files          19       18       -1     
  Lines         655      648       -7     
==========================================
- Hits          605      603       -2     
+ Misses         37       33       -4     
+ Partials       13       12       -1     

Impacted Files	Coverage Δ
audio.go	88.31% <100.00%> (+6.77%)	⬆️

... and 2 files with indirect coverage changes

[0xNF]

It'd be nice to include this feature in the Files Upload, Image Edit, and Image Variation endpoints as well

[sashabaranov]

@mdarc thank you for the PR! Would love to merge it once the test coverage issue is fixed

[mdarc]

@mdarc thank you for the PR! Would love to merge it once the test coverage issue is fixed

Coverage issue fixed. (and np! I'm glad to contribute)

[mdarc]

@mdarc thank you for the PR! Would love to merge it once the test coverage issue is fixed

All checks pass now.

One thing to note is this PR will conflict with #305 although I consider mine to be a more versatile implementation by using a Reader.

[sashabaranov]

Thank you so much!