Correct Dump file extension

BMC Dump which is implemented in phosphor-debug-collector uses ".tar.xz"
https://github.com/openbmc/phosphor-debug-collector/search?q=.tar.xz

The Dump page was incorrectly exporting as tar.gz. Fix this.

Change-Id: Id0b64a6e0ae92254484170a77e28a01f78c8d368
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/src/views/Logs/Dumps/Dumps.vue b/src/views/Logs/Dumps/Dumps.vue
index 00bbf7f..f4f6451 100644
--- a/src/views/Logs/Dumps/Dumps.vue
+++ b/src/views/Logs/Dumps/Dumps.vue
@@ -363,7 +363,7 @@
       }
     },
     exportFileName(row) {
-      let filename = row.item.dumpType + '_' + row.item.id + '.tar.gz';
+      let filename = row.item.dumpType + '_' + row.item.id + '.tar.xz';
       filename = filename.replace(RegExp(' ', 'g'), '_');
       return filename;
     },