prepare v2.1.0

[knaaptime]

• bump version
• update requirements.txt
• update gitcount notebook

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 63.41%. Comparing base (28d47f9) to head (1ebdfc6).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #184   +/-   ##
=======================================
  Coverage   63.41%   63.41%           
=======================================
  Files         118      118           
  Lines        4445     4445           
=======================================
  Hits         2819     2819           
  Misses       1626     1626           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.