Get rid of --dirty
Get rid of --dirty

For some reason building changes `Cargo.lock` which adds `-dirty` to the end of the package name of subsequent because `git describe` thinks the `librespot` working directory has changed.

For example:
`raspotify_0.31.15-2-gd716a8a~librespot.v0.3.1-72-g6c2491b-dirty_amd64.deb`

Instead of:

`raspotify_0.31.15-2-gd716a8a~librespot.v0.3.1-72-g6c2491b_amd64.deb`
dtcooper/raspotify