Update terraform plugin with v0.11.7 commands and help (#6834)

plugins/terraform/README.md

-## atom
+## Terraform oh-my-zsh plugin
 
 Plugin for Terraform, a tool from Hashicorp for managing infrastructure safely and efficiently.
 
+Current as of Terraform v0.11.7
+
 ### Requirements
 
  * [Terraform](https://terraform.io/)
@@ -12,8 +14,8 @@ Plugin for Terraform, a tool from Hashicorp for managing infrastructure safely a
 
 ### Expanding ZSH prompt with current Terraform workspace name
 
-If you want to get current Terraform workspace name in your ZSH prompt open 
-your .zsh-theme file and in a choosen place insert:
+If you want to get current Terraform workspace name in your ZSH prompt open
+your .zsh-theme file and in a chosen place insert:
 
 ```
 $FG[045]\