Upload coverage report to codecov

Editor assessment

The subject states the exact action and destination — upload coverage report to codecov — so the header alone communicates the change, and chore(ci) classifies it correctly. The imperative mood, clean punctuation, and reasonable length satisfy the hygiene checks, and no footer is needed for a pipeline-only change. The bodyless form is acceptable for a small configuration addition, though a note on why codecov was chosen or what it replaces would have added value. Clear and correct throughout, held below exemplar only by that missing rationale.