Merge pull request #103 from singer-io/feature/bump-backoff-version

bump version of backoff so that it can work with aiohttp

Author: Paul Santa Clara

setup.py

@@ -14,7 +14,7 @@
           'jsonschema==2.6.0',
           'simplejson==3.11.1',
           'python-dateutil>=2.6.0',
-          'backoff==1.3.2',
+          'backoff==1.8.0',
       ],
       extras_require={
           'dev': [