Off-by-one error on vol command

"spotify vol show" and "spotify vol up/down" results are off by one

[hnarayanan]

I honestly do not know how to fix this. This has been an error since the beginning of this project.

[davidem]

It's a funny applescript thingy. No idea why... but if I set the volume using a direct api call it is no longer off-by-one.

(never mind the white output, thats for quick debugging only)

If needed I'll update it and create PR.

[hnarayanan]

It is not needed but it will be appreciated. 😸 If it is a small change, please do raise a PR.

[davidem]

Ah, I now see there already is a 'dirty' +1 fix 😎, waiting to be merged... #146