add heatmap.pdf

tasks/export.wdl

@@ -10,7 +10,7 @@ task export{
         # seg
         cnvkit.py export seg *.cns -o ${sample_id}.seg
         # heatmap
-        cnvkit.py heatmap *.cns -o ${sample_id}.heatmap
+        cnvkit.py heatmap *.cns -o ${sample_id}.heatmap.pdf
     >>>
    
     runtime {