Fix CI: Update Python version matrix and test expectations

[Copilot]

CI was failing due to Python 3.14 (non-existent) in the test matrix and outdated test assertions incompatible with Python 3.11+ error message formats.

Changes

• .github/workflows/test.yml: Replace Python 3.14 with 3.13 in version matrix
• tests/test_main.py:
  • Update test_errors() to use substring matching for syntax error messages (Python 3.11+ changed from print("ciao") to print(...) in error text)
  • Fix test_run_bandit() file path from canary.py to tests/canary.py

Example

The error message format changed in Python 3.11+:

# Python 3.10: Missing parentheses in call to 'print'. Did you mean print("ciao")?
# Python 3.11+: Missing parentheses in call to 'print'. Did you mean print(...)?

# Before: exact match fails on newer Python
assert errors[1]["message"] == 'Missing parentheses in call to \'print\'. Did you mean print("ciao")?'

# After: substring match works across versions
assert "Missing parentheses in call to 'print'" in errors[1]["message"]

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[ioggstream]

@copilot rebase

[Copilot]

@copilot rebase

I cannot perform a rebase operation as it requires force-pushing, which is not available in my environment. The branch is currently clean with 2 commits on top of ioggstream-bump-action. If you need to rebase the branch, you'll need to do it manually or let me know if there's a specific conflict or issue that needs to be addressed instead.