Support disable spot instances.

[npalm]

The runner module hardcoded the usages of spot usags by setting market option to spot see:

terraform-aws-github-runner/modules/runners/variables.tf

Line 54 in b4838d7

variable "market_options" {

.

Would be better to make it configurable with default spot to support also on demand instances.

See also https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_InstanceMarketOptionsRequest.html

[dimisjim]

@npalm Implemented here: #657

[michaelstepner]

@npalm @dimisjim Thanks for implementing this feature! It will be super useful in my work, and I'm grateful you're providing this public good.

[michaelstepner]

Can be closed now that #657 is merged, I think. I just deployed that patch to my production server! (^-^)/ Thanks again.

[npalm]

Spot can be disabled by setting variable market_options