fix: add segmentDestination plugin to exports (#712)

Co-authored-by: Alan Charles <[email protected]>

Author: alanjcharles

packages/core/src/index.ts

@@ -4,3 +4,4 @@ export * from './types';
 export * from './mapTransform';
 export { getNativeModule } from './util';
 export { SegmentClient } from './analytics';
+export { SegmentDestination } from './plugins/SegmentDestination';