Bump jest from 26.5.3 to 26.6.0

Editor assessment

This header does its one job exactly: it names the bumped package and both version pins, jest from 26.5.3 to 26.6.0, so the change is fully identified without the diff. The build(deps-dev) classification is accurate for a development tooling bump, mood and punctuation are clean, and the PR reference is the repo's standard convention. No body is needed for a mechanical version move and none is penalized; nothing breaks and no footer is owed. The message is correct and complete for its purpose, held below exemplar only by the absence of any note on what the test-runner update brings.