Gokart

Feature
- compress tree info 192 by vaaaaanquish
- Add running gokart task on interpreter by `gokart.build` 183 by vaaaaanquish
- specific load TaskInstanceParameter 189 by vaaaaanquish
Fix bug
- Fix GCSClient bug because new version 187 by hirosassa
Update
- Add Logo 198 by saya-kawakami
- Fix documents and add tutorial 185 by vaaaaanquish
and...
Special Thanks
We have great appreciation to nishiba, an inventor of `gokart`, a great team leader and an initial member of AI/ML team at M3 inc., for his a lot of great contributions on `gokart`!

New feature
- Add parameter alias to inherits_config_params 193

BUGFIX

- Fix `ListTaskInstanceParameter` bug 199

fix

- Fix `ListTaskInstanceParameter` behavior when not specific requires method : 195

Now works following:

class Foo(gokart.TaskOnKart): hasn't requires method
foo = gokart.ListTaskInstanceParameter()

def run(self):
foo = self.load_data_frame('foo')

New feature

- Support no specification load single dataframe 180

class Task(gokart.TaskOnKart):
bar = gokart.TaskInstancePrameter()

def run(self):
df = self.load_data_frame() We won't have to write "bar" about it because it's obvious

BUGFIX
* make s3 config singleton (178) mski-iksm
* support python 3.9 (173) hirosassa

Refactoring
* fix minor deps (175) hirosassa
* Feature/use isort (177) mski-iksm
* fix badges and cleanup whitespace (174) hirosassa

minor fix and improve CI
- Suppress redundant warning messages by mski-iksm
- tox test for multiple python versions by hirosassa