Make testpypi the default option (precaution) + update tag instructions

[Saransh-cpp]

Description

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context. List any dependencies that are required for this change.

Fixes # (issue)

Type of change

Please add a line in the relevant section of CHANGELOG.md to document the change (include PR #) - note reverse order of PR #s. If necessary, also add to the list of breaking changes.

• New feature (non-breaking change which adds functionality)
• Optimization (back-end change that speeds up the code)
• Bug fix (non-breaking change which fixes an issue)

Key checklist:

• No style issues: $ pre-commit run (or $ nox -s pre-commit) (see CONTRIBUTING.md for how to set this up to run automatically when committing locally, in just two lines of code)
• All tests pass: $ python run-tests.py --all (or $ nox -s tests)
• The documentation builds: $ python run-tests.py --doctest (or $ nox -s doctests)

You can run integration tests, unit tests, and doctests together at once, using $ python run-tests.py --quick (or $ nox -s quick).

Further checks:

• Code is commented, particularly in hard-to-understand areas
• Tests added that prove fix is effective or that feature works

[codecov]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (9aeb637) 99.58% compared to head (a4cc361) 99.58%.
Report is 1 commits behind head on develop.

❗ Current head a4cc361 differs from pull request most recent head 881ee01. Consider uploading reports for the commit 881ee01 to get more accurate results

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #3452   +/-   ##
========================================
  Coverage    99.58%   99.58%           
========================================
  Files          256      256           
  Lines        20003    20003           
========================================
  Hits         19920    19920           
  Misses          83       83           

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[agriyakhetarpal]

Thanks, @Saransh-cpp! The newer Windows failures here are just a one-off case because there is a cache mismatch due to #3454. We could delete some of the newer cache entries so that they don't affect other PRs.

[brosaplanella]

Looks good, thanks!

[arjxn-py]

Thanks @Saransh-cpp Looks good, happy to follow up with @agriyakhetarpal's suggestion.