Example code update for newer versions of terraform

Author: drastawi

.gitignore

@@ -4,6 +4,7 @@
 example.tf
 terraform.tfplan
 terraform.tfstate
+.terraform.lock.hcl
 bin/
 dist/
 modules-dev/

website/docs/index.html.markdown

@@ -16,6 +16,14 @@ Use the navigation to the left to read about the available resources.
 
 ```hcl
 # Configure the PagerDuty provider
+terraform {
+  required_providers {
+    pagerduty = {
+      source  = "pagerduty/pagerduty"
+    }
+  }
+}
+
 provider "pagerduty" {
   token = var.pagerduty_token
 }