fix(docs): fix variable name create_service_linked_role_spot in readme (#750)

Fixes #736.

Author: hkdobrev

Diff for: README.md

@@ -137,7 +137,7 @@ For local development you can build all the lambdas at once using `.ci/build.sh`
 
 #### Service-linked role <!-- omit in toc -->
 
-To create spot instances the `AWSServiceRoleForEC2Spot` role needs to be added to your account. You can do that manually by following the [AWS docs](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/spot-requests.html#service-linked-roles-spot-instance-requests). To use terraform for creating the role, either add the following resource or let the module manage the the service linked role by setting `create_service_linked_role` to `true`. Be aware this is an account global role, so maybe you don't want to manage it via a specific deployment.
+To create spot instances the `AWSServiceRoleForEC2Spot` role needs to be added to your account. You can do that manually by following the [AWS docs](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/spot-requests.html#service-linked-roles-spot-instance-requests). To use terraform for creating the role, either add the following resource or let the module manage the the service linked role by setting `create_service_linked_role_spot` to `true`. Be aware this is an account global role, so maybe you don't want to manage it via a specific deployment.
 
 ```hcl
 resource "aws_iam_service_linked_role" "spot" {