TypeError in keyword argument backend_directory on misspecified --backends option

Calling:

scripts/larvatagger open /path/to/data/file --backends=/path/to/backend/directory --browser

fails at src/cli_open.jl:62 with error message TypeError: in keyword argument backend_directory, expected String, got a value of type SubString{String}.

While argument --backends should point at the parent directory of the desired backend, the error is still a bug, possibly due to a change in dependency DocOpt (not verified).

Thanks to Adrien Bouchet and Anqi Zhou for reporting the issue.