Migrate Python package name

[seanjtaylor]

We now own the prophet project on PyPI, which means we can use prophet as our top-level package name if we wanted.

Proposal 1: deprecate fbprophet as a package name

Steps:

1. move all code to prophet package
2. create a second package fbprophet that depends on prophet and maintains import compatibility, issue warning at install time
3. next release: issue warning to use new package name at import time
4. 2nd release: stop updating fbprophet and use prophet exclusively.

Proposal 2: keep fbprophet indefinitely and tie releases together

Everything from Proposal 1 without steps 3 and 4.

Open Questions

• How do we make it possible for people to continue using the old prophet package.
• Do we need to copy all old releases over to the new package name?

[bletham]

I think (1) makes the most sense, and that we should try to migrate people from importing fbprophet to importing prophet. The compatibility layer that just imports everything from prophet makes a lot of sense and shouldn't be too hard.

• Migrating old prophet package: I guess it should be migrated to a different pypi name? Maybe something like prophet_finance? Maybe to help that migration we should have some period of time after that is done but before we move fbprophet to prophet where installing prophet just produces an error that the package name has moved (like https://pypi.org/project/pytorch/ ).

• Copy old releases: I don't think we really need to. The old versions are all here in github, and we don't ship binaries anyway so there isn't anything on pypi that isn't here.