ci: run the pytest step under bash so test failures fail the job

The "Test with pytest and report coverage" step runs two commands in one
block. On Windows the default pwsh shell only propagates the LAST command's
exit code, so a failing `coverage run -m pytest` followed by a passing
`coverage report` was reported as a green job — a false pass that masked a
real test failure. Forcing `shell: bash` (run with -eo pipefail) aborts on the
pytest failure on every OS.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: thodson-usgs

.github/workflows/python-package.yml

@@ -47,6 +47,10 @@ jobs:
           python -m pip install --upgrade pip
           pip install .[test,nldi]
       - name: Test with pytest and report coverage
+        # Force bash on Windows too: the default pwsh shell only propagates the
+        # last command's exit code, so a pytest failure followed by a passing
+        # ``coverage report`` was reported as a green job (false pass).
+        shell: bash
         run: |
           coverage run -m pytest tests/
           coverage report -m