The API of `Dvcfile.dump` has been changed to
`dump(stage, update_pipeline=True, update_lock=True)`,
which will make it to always dump by default to both files,
and provide flags to suppress one or the other.
Fixes#4235
* dvc: use lockfile as yaml instead of json
* refactor Dvcfile into Pipeline file and Single stage file
* fix tests
* dvc: fix outputs
* add more tests for collection of outputs
* add tests for data cloud/get/import/ls
* tests: test for checkouts
* Allow other checksums other than md5
* tests: use iterdir instead of os.listdir
* cleanup errors reported by cc and ds
* utils: throw DvcException instead of plain Exception
* tests: use yaml.load instead of json.load
* run: split assignments
* Update dvc/stage/exceptions.py
Co-authored-by: Ruslan Kuprieiev <[email protected]>
Saugat Pachhai
