newer version of open tracing

[tarbaig]

Checklist

• [ X ] I have included information about relevant versions
• [ X ] I have verified that the issue persists when using the master branch of Faust.

Steps to reproduce

Install faust together with a current version of jaeger-client (which requires opentracing>=2.1)

Expected behavior

No version conflict should arise

Actual behavior

faust claims to be unable to work with opentracing>=2.0.0

Full traceback

ERROR: jaeger-client 4.3.0 has requirement opentracing<3.0,>=2.1, but you'll have opentracing 1.3.0 which is incompatible.

Versions

• Python version
  3.7
• Faust version
  faust-streaming-0.3.0
• Operating system
  linux

According to this issue in the original project just bumping the version number here should be enough to enable opentracing>2.0.0.

The reason it was not upgraded in the original project was a possible incompatibility in robinhoods closed source internal tracing framework.

I tried it locally and all tests work.

[patkivikram]

Sounds good - we use it for datadog with opentracing>=2.0.0. Can you create a PR?