Add support for using secret manager environment variables in Cloud Function

[AronllStone]

Hello All,
I would like to add support for using secret manager environment variables to this module.

New variable: secret_environment_variables

Supported by Google provider since version 4.11.0
Available for Terraform >= v0.13.0

Example of usage:

module "http_function" {
  source  = "terraform-google-modules/event-function/google"
  ...
  secret_environment_variables = [
    {
      key        = "ACCESS_TOKEN"
      project_id = "111111"
      secret     = "SECRET_ACCESS_TOKEN"
    },
    {
      key     = "CLIENT_ID"
      secret  = "SECRET_CLIENT_ID"
      version = "1"
    }
  ]
  ...
}

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[bharathkkb]

Thanks for the PR @AronllStone
Could we also showcase this in one of the examples?

[AronllStone]

@bharathkkb, could you please help with logs from event-function-int-trigger check?
I can't understand why this check fell down

[bharathkkb]

@AronllStone The function seems to be failing to become ready

        	Error:      	Received unexpected error:
        	            	FatalError{Underlying: error while running command: exit status 1; ╷
        	            	│ Error: Error waiting for Creating CloudFunctions Function: timeout while waiting for state to become 'done: true' (last state: 'done: false', timeout: 5m0s)
        	            	│ 
        	            	│   with module.localhost_function.google_cloudfunctions_function.main,
        	            	│   on ../../main.tf line 91, in resource "google_cloudfunctions_function" "main":
        	            	│   91: resource "google_cloudfunctions_function" "main" {
        	            	│ 
        	            	╵}

I have kicked off another build and will try to see if anything shows up in the logs

[comment-bot-dev]

@AronllStone
Thanks for the PR! 🚀
✅ Lint checks have passed.

[AronllStone]

Hey, @bharathkkb & @morgante!
Is there any chance to approve/merge this PR? 😄