Bump pymongo from 3.3.0 to 3.7.0

Bumps [pymongo](https://github.com/mongodb/mongo-python-driver) from 3.3.0 to 3.7.0.
- [Release notes](https://github.com/mongodb/mongo-python-driver/releases)
- [Changelog](https://github.com/mongodb/mongo-python-driver/blob/master/doc/changelog.rst)
- [Commits](mongodb/mongo-python-driver@3.3.0...3.7.0)

Signed-off-by: dependabot[bot] <support@dependabot.com>

setup.py

@@ -23,7 +23,7 @@
     'click==6.7',
     'Flask',
     'cerberus',
-    'pymongo==3.3.0',
+    'pymongo==3.7.0',
 ]