Update Terraform.gitignore

Ignore override files as they are usually used locally
to override resources or variables without changing the code
More info: https://www.terraform.io/docs/configuration/override.html

Terraform.gitignore

@@ -13,3 +13,9 @@ crash.log
 # version control.
 #
 # example.tfvars
+
+# Ignore override files as they are usually used to override ressources locally
+override.tf
+override.tf.json
+*_override.tf
+*_override.tf.json