Add default value for the subnetwork var, fix minor readme issues

Author: averbuks

examples/automatic-labelling-from-repository/README.md

@@ -9,7 +9,7 @@ principal email address of the account responsible for causing the events.
 
 ## Usage
 
-To provision this example, populate `terraform.tfvars` with the [required variables][variables] and run the following commands within
+To provision this example, populate `terraform.tfvars` with the [required variables](#inputs) and run the following commands within
 this directory:
 
 - `terraform init` to initialize the directory
@@ -72,4 +72,3 @@ following APIs enabled:
 [repository-function-submodule-requirements]: ../../modules/repository-function/README.md#requirements
 [repository-function-submodule]: ../../modules/repository-function
 [terraform-site]: https://terraform.io/
-[variables]: ./variables.tf

examples/automatic-labelling-from-repository/variables.tf

@@ -32,5 +32,5 @@ variable "zone" {
 variable "subnetwork" {
   type        = string
   description = "The name or self_link of the subnetwork to create compute instance in."
-  default     = ""
+  default     = "default"
 }

examples/delete-vms-without-cmek/README.md

@@ -8,7 +8,7 @@ which responds to Compute VM creation events by deleting any VM instances create
 
 ## Usage
 
-To provision this example, populate `terraform.tfvars` with the [required variables][variables] and run the following commands within
+To provision this example, populate `terraform.tfvars` with the [required variables](#inputs) and run the following commands within
 this directory:
 
 - `terraform init` to initialize the directory
@@ -63,4 +63,3 @@ following APIs enabled:
 [root-module-requirements]: ../../README.md#requirements
 [root-module]: ../..
 [terraform-site]: https://terraform.io/
-[variables]: ./variables.tf