How to create "transitional" package?
Yesterday, I released msgpack-0.5, which was msgpack-python.
Both packages provide "msgpack" python package.
I used msgpack in early days, but easy_install crawling website
and download msgpack-1.0.0.tar.gz, which is msgpack for C instead
of Python package I upload to PyPI.
So I renamed msgpack-python but I really dislike it.
Now pip doesn't such silly crawling so I decided to rename back
To ease transition, I follow what uritemplate.py  did (which was
migrated to uritemplate).
I released msgpack-python 0.5. It is empty package.
But it's metadata contains `install_requires=["msgpack>=0.5"]`.
Sadly, this breaks upgrading from old version via `pip install -U
* Install msgpack-0.5 (overwrite msgpack-python 0.4.7)
* Uninstall msgpack-python 0.4.7 (removes msgapck 0.5!)
* Install msgpack-python 0.5 (empty!)
I found uritemplate.py has same issue. Maybe pip's behavior was
changed after migration of uritemplate.py to uritemplate.
Now what can I do for smooth transition?
I don't want to back to msgpack-python again.
INADA Naoki <songofacandy at gmail.com>