Align regex for device ID's for gateways

[noursaidi]

No description provided.

[grafnu]

I'd do a bit more of a scan to make sure there's not other rogue instances, otherwise we're likely to come across this again and again! E.g.,

peringknife@peringknife-glaptop4:~/udmi$ fgrep -e -[0-9] -r schema/
schema/model_system.json:              "pattern": "^[A-Z]{2,6}-[0-9]{1,6}$"
schema/model_gateway.json:      "pattern": "^[A-Z]{2,6}-[0-9]{1,6}$",
schema/model_gateway.json:        "pattern": "^[A-Z]{2,6}-[0-9]{1,6}$"
schema/state_validation.json:        "^[A-Z]{2,6}-[0-9]{1,6}$": {
schema/envelope.json:      "pattern": "^[A-Z]{2,6}-[0-9]{1,6}$"
schema/envelope.json:      "pattern": "^[A-Z]{2,6}-[0-9]{1,6}$"