Update requirements.txt and setup.py

[nsano-rururu]

Description

Update requirements.txt and setup.py

memo

• The latest version of envparse will be released in 2015.
• I'm worried that statsd-tags doesn't have a github repository. The latest release is 2016.
  It is necessary to consider changing to another library when it stops working due to python version upgrade
  Candidates to change
  https://github.com/jsocol/pystatsd
  https://github.com/lirsacc/statsd_client_python
• The latest version of exotel will be released in 2017.

Checklist

• I have reviewed the contributing guidelines.
• I have included unit tests for my changes or additions.
• I have successfully run make test-docker with my changes.
• I have manually tested all relevant modes of the change in this PR.
• I have updated the documentation.
• I have updated the changelog.

Questions or Comments

[jertel]

Thanks for updating all these deps. I think it will help avoid some problems (not all) that we occasionally see in Discussions.