chore(zipkin): export ExporterConfig (#1474)

Co-authored-by: Daniel Dyla <[email protected]>

Author: shivkanya9146

packages/opentelemetry-exporter-zipkin/src/index.ts

@@ -14,5 +14,6 @@
  * limitations under the License.
  */
 
-export * from './zipkin';
 export * from './platform';
+export { ExporterConfig } from './types';
+export * from './zipkin';