AWS Deploy: Instance type should be string

[REASY]

• instance_type is a string
• set payload before using it

Got an error during deploy:

:aws:deploy
{
  "title": "art/austin-prod-200k-plans-from-urbnasim_reasyuATgmail_com",
  "git_user_email": "reasyuATgmail_com",
  "deploy_type_tag": "null",
  "branch": "AK/#2624-merg-urbansim-with-austin",
  "commit": "d9644ad64a1432000602cd9c1ec8da8640152f00",
  "deploy_mode": "config",
  "configs": "test/input/texas/austin-prod-100k.conf",
  "experiments": "null",
  "execute_class": "beam.sim.RunBeam",
  "execute_args": "null",
  "max_ram": "300g",
  "storage_size": 256,
  "batch": false,
  "s3_publish": true,
  "instance_type": c5.9xlarge,
  "region": "us-east-2",
  "shutdown_wait": "15",
  "shutdown_behaviour": "terminate",
  "command": "deploy",
  "run_grafana" : false,
  "is_spot" : false,
  "min_cores": 0,
  "max_cores": 0,
  "min_memory": 0,
  "max_memory": 0
}
Please note that if you set isSpot to true then it could take an excessive time period. In fact it could time out at 15 minutes and still complete later on. ALSO! volumes using spot instances must be MANUALLY deleted. This is done so you do not lose data in the case of a premature shutdown.
:aws:deploy FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':aws:deploy'.
> Could not parse request body into json: Unrecognized token 'c5': was expecting ('true', 'false' or 'null')
   at [Source: (byte[])"{
    "title": "art/austin-prod-200k-plans-from-urbnasim_reasyuATgmail_com",
    "git_user_email": "reasyuATgmail_com",
    "deploy_type_tag": "null",
    "branch": "AK/#2624-merg-urbansim-with-austin",
    "commit": "d9644ad64a1432000602cd9c1ec8da8640152f00",
    "deploy_mode": "config",
    "configs": "test/input/texas/austin-prod-100k.conf",
    "experiments": "null",
    "execute_class": "beam.sim.RunBeam",
    "execute_args": "null",
    "max_ram": "300g",
    "storage_size": 256,
    "batch": false,
    "s3_publish":"[truncated 268 bytes]; line: 16, column: 23] (Service: AWSLambda; Status Code: 400; Error Code: InvalidRequestContentException; Request ID: 35029b7e-3c1a-47bd-9892-e62121f21e11)

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This change is 

[JustinPihony]

I couldve swore I tested this - odd it is just being caught now - thanks for catching.