Fix type errors with maplibre-gl 6.0–6.2

[db9795]

Problem

The peer dependency allows maplibre-gl >=6.0.0, but the published typings only compile from 6.3.0 on. StyleControlEventType used Event<"style.set">, and maplibre's Event class only became generic in 6.3.0. TypeScript projects on 6.0–6.2 without skipLibCheck fail to build with:

error TS2315: Type 'Event$1' is not generic.

Runtime behavior was never affected. CI didn't catch it because it only runs against the locked version (6.9.1).

Changes

• Drop the type argument from Event in the style.set event type. Evented<…> is already generic in 6.0.0, so control.on("style.set", e => e.style) stays fully typed. The only difference is that e.type is now typed as string instead of the literal "style.set".
• README: note that the control is built and tested against maplibre-gl v6.
• Patch changeset.

Fixing the typings instead of raising the peer range to >=6.3.0 keeps users on 6.0–6.2 installable without --legacy-peer-deps.

Testing

Typecheck and tests pass against maplibre-gl 6.0.0, 6.2.0, 6.3.0, 6.9.1 (locked) and 6.12.0 (latest). Before this change, typecheck failed on 6.0.0–6.2.0.