[build] remove maintainer password from PyPI publish workflow in lieu of trusted publisher attestation

[zacharyburnett]

Resolves SCSB-199

• add a Trusted Publisher configuration to the PyPI project by visiting https://pypi.org/manage/project/stsci.stimage/settings/publishing/?provider=github&owner=spacetelescope&repository=stsci.stimage&workflow_filename=build.yml
• remove pypi_token (STScI PyPI maintainer password) from build workflow
• wait for issue with reusable workflows to be resolved in pypa/warehouse

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.71%. Comparing base (8449f38) to head (fbbfb02).

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #62   +/-   ##
=======================================
  Coverage   85.71%   85.71%           
=======================================
  Files           1        1           
  Lines           7        7           
=======================================
  Hits            6        6           
  Misses          1        1           

☔ 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.