rust: 1.39 -> 1.40
Update common to get rustc v1.40
"common": {
"ref": "master",
"repo": "ssh://git@github.com/dfinity-lab/common",
- "rev": "233f63f23f0a207f291693fc1983a92a53e28b59",
+ "rev": "72c5d937835d8f9f29914254fe98042f28bc2fff",
"type": "git"
},
"dfinity": {
