Add test for target_index_settings to rollup specification

Signed-off-by: Aleksandr Tuliakov <[email protected]>

Author: MrChaos1993

tests/default/rollup/jobs.yaml

@@ -39,6 +39,9 @@ chapters:
               unit: Minutes
           source_index: books
           target_index: books_by_order_date
+          target_index_settings:
+            index.codec: zlib
+            index.codec.compression_level: 6
           page_size: 1
           delay: 0
           continuous: false
@@ -71,6 +74,9 @@ chapters:
         _id: books
         rollup:
           rollup_id: books
+          target_index_settings:
+            index.codec: zlib
+            index.codec.compression_level: 6
   - synopsis: Delete an index rollup job.
     path: /_plugins/_rollup/jobs/{id}
     method: DELETE