list-files should output file names relative to the current working directory

[trygveaa]

The list-files command currently outputs file names relative to the git root directory. This means that if you want to run e.g. eslint $(lint-filter -b branch list-files), you have to do that from the root directory. This may be inconvenient, especially if the frontend code is in a subdirectory (for example in a repo together with the backend).

[trygveaa]

This can be done either by passing the --relative option to git diff, or by changing the paths yourself. The difference is that with the --relative option, changes outside of the current working directory is excluded. What do you think?