chore: fixed network firewall policy readme (#519)

Author: imrannayer

modules/network-firewall-policy/README.md

@@ -1,6 +1,6 @@
 # Google Cloud VPC Firewall Policy
 
-This module allows creation of [Global](https://cloud.google.com/firewall/docs/network-firewall-policies) and [Regional](https://cloud.google.com/firewall/docs/regional-firewall-policies) Network Firewall Policy and [Rules](https://cloud.google.com/firewall/docs/firewall-policies-rule-details). It can also attach network firewall policy to multiple VPCs. Module will create a `Global` network firewall policy if a value is provided for the variable `policy_region`, otherwise a `Regional` network firewall policy will be created. Module can create both [Cloud Firewall Essentials](https://cloud.google.com/firewall/docs/about-firewalls#firewall-essentials) and [Cloud Firewall Standard](https://cloud.google.com/firewall/docs/about-firewalls#firewall-standard) tier rules. Firewall Rules and Target VPC attachment is optional.
+This module allows creation of [Global](https://cloud.google.com/firewall/docs/network-firewall-policies) and [Regional](https://cloud.google.com/firewall/docs/regional-firewall-policies) Network Firewall Policy and [Rules](https://cloud.google.com/firewall/docs/firewall-policies-rule-details). It can also attach network firewall policy to multiple VPCs. Module will create a `Regional` network firewall policy if a value is provided for the variable `policy_region`, otherwise a `Global` network firewall policy will be created. Module can create both [Cloud Firewall Essentials](https://cloud.google.com/firewall/docs/about-firewalls#firewall-essentials) and [Cloud Firewall Standard](https://cloud.google.com/firewall/docs/about-firewalls#firewall-standard) tier rules. Firewall Rules and Target VPC attachment is optional.
 
 ##  Module Format