Update OpenTracing dependencies. (#78)

Author: pglombardo

setup.py

@@ -13,8 +13,8 @@
       zip_safe=False,
       install_requires=['autowrapt>=1.0',
                         'fysom>=2.1.2',
-                        'opentracing>=1.2.1,<1.3',
-                        'basictracer>=2.2.0'],
+                        'opentracing>=1.2.1,<2.0',
+                        'basictracer<3.0'],
       entry_points={
                     'instana':  ['string = instana:load'],
                     'flask':    ['flask = instana.flaskana:hook'],