feat: Make MySQL CloudSQL zone optional (#572)

Co-authored-by: Awais Malik <[email protected]>

modules/mysql/README.md

@@ -63,7 +63,7 @@ Note: CloudSQL provides [disk autoresize](https://cloud.google.com/sql/docs/mysq
 | user\_labels | The key/value labels for the master instances. | `map(string)` | `{}` | no |
 | user\_name | The name of the default user | `string` | `"default"` | no |
 | user\_password | The password for the default user. If not set, a random one will be generated and available in the generated\_user\_password output variable. | `string` | `""` | no |
-| zone | The zone for the master instance, it should be something like: `us-central1-a`, `us-east1-c`. | `string` | n/a | yes |
+| zone | The zone for the master instance, it should be something like: `us-central1-a`, `us-east1-c`. | `string` | `null` | no |
 
 ## Outputs
 

modules/mysql/variables.tf

@@ -79,6 +79,7 @@ variable "edition" {
 variable "zone" {
   description = "The zone for the master instance, it should be something like: `us-central1-a`, `us-east1-c`."
   type        = string
+  default     = null
 }
 
 variable "secondary_zone" {

modules/safer_mysql/README.md

@@ -211,7 +211,7 @@ mysql -S $HOME/mysql_sockets/myproject:region:instance -u user -p
 | user\_name | The name of the default user | `string` | `"default"` | no |
 | user\_password | The password for the default user. If not set, a random one will be generated and available in the generated\_user\_password output variable. | `string` | `""` | no |
 | vpc\_network | Existing VPC network to which instances are connected. The networks needs to be configured with https://cloud.google.com/vpc/docs/configure-private-services-access. | `string` | n/a | yes |
-| zone | The zone for the master instance, it should be something like: `a`, `c`. | `string` | n/a | yes |
+| zone | The zone for the master instance, it should be something like: `a`, `c`. | `string` | `null` | no |
 
 ## Outputs
 

modules/safer_mysql/variables.tf

@@ -70,6 +70,7 @@ variable "edition" {
 variable "zone" {
   description = "The zone for the master instance, it should be something like: `a`, `c`."
   type        = string
+  default     = null
 }
 
 variable "secondary_zone" {