Update 'defaults'

defaults

@@ -2,5 +2,5 @@
     "reference_gtf_file":"oss://pgx-reference-data/reference/spladder/SplAdder/data/reference/Homo_sapiens.GRCh38.103.gtf",
     "spladder_docker":"registry.cn-shanghai.aliyuncs.com/pgx-docker-registry/spladder:v2.4.2",
     "spladder_cluster":"OnDemand bcs.a2.3xlarge img-ubuntu-vpc",
-    "disk_size":"500"
+    "disk_size":"200"
     }