docs: update to generic values

Author: Rahul-4480

examples/complete/.header.md

@@ -3,9 +3,9 @@
 
 ```hcl
 # Required Parameters
-public_subnet_ids              = ["subnet-050928489741239", "subnet-98347019238472343"]
-private_subnet_ids             = ["subnet-09483509823434", "subnet-57093487509234870"]
-vpc_id                         = "vpc-43523452345265253"
+public_subnet_ids              = ["subnet-xxxxxxxx", "subnet-xxxxxxxx"]
+private_subnet_ids             = ["subnet-xxxxxxxx", "subnet-xxxxxxxx"]
+vpc_id                         = "vpc-xxxxxxxx"
 atlantis_url                   = "example.your-domain.com"
 atlantis_gh_user               = "your-github-username"
 atlantis_repo_allowlist        = ["repo1", "repo2"]