change gammatone requirement to Gammatone

[quancs]

Hello, Torchmetrics requires SRMRpy for validating its implementations. However, SRMRpy install Gammatone by https://github.com/detly/gammatone/archive/master.zip#egg=Gammatone which will be skipped for pypi. So, this pull request change it to git+https://github.com/detly/gammatone, which will not affect the installtion of SRMRpy, but will make the requirements in Torchmetrics works. see the discussion here Lightning-AI/torchmetrics#1792 (comment)

[Borda]

On this note, gammatone shall be released on PyPI otherwise, this won't be picked by PR as they do not allow packages outside its registry so no URL or git references to a package 🐰

[quancs]

On this note, gammatone shall be released on PyPI otherwise, this won't be picked by PR as they do not allow packages outside its registry so no URL or git references to a package 🐰

The response from the author of gammatone:
detly/gammatone#16 (comment)

[jfsantos]

Apologies for the delay, I didn't understand from the response from the author of gammatone and subsequent responses if Gammatone was published to PyPI or not. Can you confirm if this is still needed?