update default version of down_load_console to v2.6.0

tools/download_console.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 package_name="console.tar.gz"
-default_version="1.2.0"
+default_version="2.6.0"
 download_version="${default_version}"
 specify_console=0
 solc_suffix=""