Bump requests version

This change alters the setup.py file for requests and simplejson versions.

Users on various platforms (and using various packages that also use the requests library && simplejson) have run into dependency issues caused by version pinning.

Webhook Release 2.0.1

Added:

• Webhook Class method
• Examples:
  • Multipiece
  • Create / Remove webhook endpoints

Release v2.0.0

• Update default API version to 2018-02-08
• Migrate shippo config constants to shippo.config namespace
• Python 3.5+ support
• Remove async param

Release v1.6.2

Merge pull request #44 from goshippo/oauth-token-support

Add OAuth api token support

Display DeprecationWarning on Shippo only

Minor Improvements

• Only show DeprecationWarning for shippo package.

Release v1.2.1

Bugfixes

• add version.py to shippo

Release v1.2.0

Behavioural Changes

• [WARNING] Changed keyword for creating shipments and transactions synchronously from sync=True to async=False

Improvements

• Removed polling for shipments and transactions calls
• Fixed and added tests

Minor Improvements

• Added fixtures to our tests using vcr
• Added Travis-CI
• Added badges to the README
• Bumped unittest version