nix/sources.json: update common to fix unnecessary repeated builds
This pulls in:
"common": {
"ref": "master",
"repo": "ssh://git@github.com/dfinity-lab/common",
- "rev": "f0253a3a0ce2b5d97dbf887cb0d3fcdb975b5b6a",
+ "rev": "16b88b24e34e9f766e32804af50d16d93a48fd2c",
"type": "git"
},
"dfinity": {
