FIX accept pathlib based path as argument for LocalTarget

[orsinium]

Description

Accept pathlib.PosixPath, py._path.local.LocalPath and other path based objects as argument for FileSystemTarget.

Motivation and Context

Fix #2322

Have you tested this? If so, how?

I have included unit tests.

[dlstadther]

Looks reasonable to me

[orsinium]

Added fixes from @dlstadther's review.

[dlstadther]

LGTM

[Tarrasch]

Wow, was it this easy to start supporting it?

Maybe ping @bjlange as the one that opened the ticket in the first place.

---

By the way, can you look if there's any documentation you can add? Maybe an example usage of the new functionality as class docs for FileSystemTarget?

[bjlange]

Amazing! Thanks @orsinium

[orsinium]

Added usage example in docstring.

[orsinium]

What about this PR? Does anyone have any changes requests?

[josham]

@Tarrasch @dlstadther Any reason this isn't yet merged?

[dlstadther]

@josham The code looks good, but the tests aren't passing

[orsinium]

I couldn't tame the doctest, so I've just dropped usage example >.<

[orsinium]

Travis is ok now

[Tarrasch]

I couldn't tame the doctest, so I've just dropped usage example >.<

Really? Why? Can't you just remove one layer of > and it won't run doctest? It still will be super useful to have the docs!

[orsinium]

Wow, Tarrasch, don't worry about it too much, please. I've returned it as you said. Thank you for a good idea :)

[orsinium]

Ok, it doesn't work:
https://travis-ci.org/spotify/luigi/jobs/495852917

[josham]

I think you want to remove .. code-block:: python from the docs

[orsinium]

In this case it will be broken in the readthedocs api reference.

[Tarrasch]

Just fyi you can test the docs locally too you know: https://github.com/spotify/luigi/blob/master/CONTRIBUTING.rst#writing-documentation

[orsinium]

I know. BTW, I've made a few fixes for CONTRIBUTING.rst in another PR. However, sometimes it can't help because I can check locally only "*-core" tests, without hdfs.

I've pushed this code with broken doctest to show that your idea how to bypass this check doesn't work.

[orsinium]

now it works

[Tarrasch]

Thanks for this addition @orsinium!

[orsinium]

Wow. Thank you, fellows. Sorry for long review process :)

[bjlange]

🙌