Add ikv-store benchmark fixture

src/main/java/com/benchmark/fixtures/FixtureFactory.java

@@ -6,6 +6,7 @@ public class FixtureFactory {
         return switch (type) {
             case "in-memory"       -> new InMemoryFixture();
             case "memory-mapped-file" -> new MemoryMappedFileFixture();
+            case "ikv-store"       -> new IkvStoreFixture();
             case "datastore4j"      -> new DataStore4jFixture();
             case "leveldb"          -> new LevelDbFixture();
             case "lmdb"            -> new LmdbFixture();