Avoid duplicate dependency on requests

[jleclanche]

The duplicate dependency is causing issues with pip on Python 2.7.

Context:

• Duplicate requests dependency (causes issues on Python 2) #447
• Extras not getting installed when the package that includes the extras has already been installed  pypa/pip#4957

Fixes #447

---

Testing this:

• Ran pip install . in a python2.7 virtualenv in the root stripe-python folder
• Verified python2.7 -c "import requests" does not crash
• Installed pipdeptree and verified requests is not showing up twice:

pipdeptree==0.13.0
  - pip [required: >=6.0.0, installed: 10.0.1]
pyOpenSSL==18.0.0
  - cryptography [required: >=2.2.1, installed: 2.2.2]
    - asn1crypto [required: >=0.21.0, installed: 0.24.0]
    - cffi [required: >=1.7, installed: 1.11.5]
      - pycparser [required: Any, installed: 2.18]
    - enum34 [required: Any, installed: 1.1.6]
    - idna [required: >=2.1, installed: 2.7]
    - ipaddress [required: Any, installed: 1.0.22]
    - six [required: >=1.4.1, installed: 1.11.0]
  - six [required: >=1.5.2, installed: 1.11.0]
setuptools==40.0.0
stripe==2.0.1
  - requests [required: >=2, installed: 2.19.1]
    - certifi [required: >=2017.4.17, installed: 2018.4.16]
    - chardet [required: >=3.0.2,<3.1.0, installed: 3.0.4]
    - idna [required: >=2.5,<2.8, installed: 2.7]
    - urllib3 [required: >=1.21.1,<1.24, installed: 1.23]
wheel==0.31.1

[ob-stripe]

Left a minor comment. Thanks for the report and the PR @jleclanche! Great work as usual.

[ob-stripe]

Super minor nit, but could you change the condition to use >= instead of >?

We don't support Python 3.0 so this doesn't really change anything, but it bothers me that this implies that if 3.0 were supported, then requests would not be necessary.

[jleclanche]

Done

[ob-stripe]

Released as 2.0.2. Thanks again @jleclanche :)

[jleclanche]

🤔 I just finished working around this issue.

Thanks for the release :)