fix bug

defaults

 {
     "docker": "registry.cn-shanghai.aliyuncs.com/pgx-docker-registry/bamdst:1.0.9",
     "disk_size": "200",
-    "cluster_config": "OnDemand bcs.a2.large img-ubuntu-vpc"
+    "cluster_config": "OnDemand bcs.b2.3xlarge img-ubuntu-vpc"
 }

tasks/bamdst.wdl

     command <<<
         set -o pipefail
         set -e
-
-        bamdst -p ${bed} -o ./ ${bam}
+        mkdir -p /cromwell_root/tmp/bamdst
+        bamdst -p ${bed} -o /cromwell_root/tmp/bamdst ${bam}
+        cd /cromwell_root/tmp/bamdst
         cp chromosomes.report ${sample}_chromosomes.report
         cp coverage.report ${sample}_coverage.report
         cp depth_distribution.plot ${sample}_depth_distribution.plot