HasLayer and Async add async callbacks

What's Changed

• Add SetLayoutProperty method by @mklimo in #135
• feat: add HasLayer and HasSource methods to check for layer and sourc… by @MatejMa2ur in #138

Breaking changes

• Add capability for async callbacks to be registered for map events by @jonaskpb in #141

New Contributors

• @mklimo made their first contribution in #135
• @jonaskpb made their first contribution in #141

Full Changelog: v1.2.0...v1.3.0