added coder param defaults

git-config/main.tf

@@ -29,6 +29,7 @@ variable "default_user_email" {
 data "coder_parameter" "user_email" {
   name = "user_email"
   type = "string"
+  default = ""
   description = "Email to store in git-config for this workspace. Leave empty to populate with workspace owner email."
   display_name = "Git config user.email"
   mutable = false
@@ -37,6 +38,7 @@ data "coder_parameter" "user_email" {
 data "coder_parameter" "username" {
   name = "username"
   type = "string"
+  default = ""
   description = "Username to store in git-config for this workspace. Leave empty to populate with workspace owner name."
   display_name = "Git config user.name"
   mutable = false