Update dependency @types/mocha to v8.2.2

Editor assessment

A routine Renovate type-definition bump, cleanly done. `update dependency @types/mocha to v8.2.2` is imperative, lowercase, period-free, and 40 characters, with the `deps` scope doing standard grouping work. Since @types packages affect only compilation, never runtime, `chore(deps)` is the correct classification and any mistaken minor inference is harmless. The bodyless Renovate style is acceptable for this class of change — type stubs rarely have a changelog worth linking — though a `Refs` footer to the upstream release would cost nothing. Non-breaking, machine-parseable, and semantically dull in the best way. Nothing to correct.