fix: Export migration APIs. (#302)

Author: kinyoklion

packages/shared/sdk-server/src/api/data/LDMigrationOpEvent.ts

@@ -60,7 +60,7 @@ export type LDMigrationMeasurement =
  * Event used to track information about a migration operation.
  *
  * Generally this event should not be created directly and instead an
- * {@link MigrationOpTracker} should be used to generate it.
+ * LDMigrationOpTracker should be used to generate it.
  */
 export interface LDMigrationOpEvent {
   kind: 'migration_op';

packages/shared/sdk-server/src/api/index.ts

@@ -1,6 +1,7 @@
 export * from './data';
 export * from './options';
 export * from './LDClient';
+export * from './LDMigration';
 export * from './interfaces/DataKind';
 export * from './subsystems/LDFeatureStore';