Predict serviceId based on service runner location

[alx-andru]

The prediction of the serviceId is based on a hard-coded location (America/Los_Angeles) which, when run in a different time zone can cause a date change and the prediction is off by a day. My guess might be that the initial tests were run against the us-west2 Cloud Run location and fully in Terraform Cloud.

Example when applying following resource with the Execution Mode set to Local:

resource "google_endpoints_service" "openapi_service" {
  service_name = "my-service-name"
  project      = "my-gcp-projectId"
  openapi_config = sensitive(templatefile("./swagger.json", {
    host = "my-service-name"
  }))
}

I'm presented with the predicted service Id which is a day behind: "2021-08-08r5" -> "2021-08-07r0"

  # module.my-api-cloud-endpoints-module.google_endpoints_service.openapi_service will be updated in-place
  ~ resource "google_endpoints_service" "openapi_service" {
      ~ config_id      = "2021-08-08r5" -> "2021-08-07r0"
        id             = "my-service-name"
      ~ openapi_config = (sensitive)
        # (5 unchanged attributes hidden)
    }

Rather than setting a hard-coded location, we are utilizing the system Location.

Note I'm not a go developer and based my proposed change purely on reading the source code and finding the hopeful right use of Location from the Go-Lang time documentation.

Related issue: https://github.com/hashicorp/terraform-provider-google/issues/6713

In draft to allow for discussion around the proposed change