Make resource repository_deploy_key read_only a bool, and expand the …

…example (integrations#2044)

* Make resource repository_deploy_key read_only a bool, and expand the example

* Clarify used provider

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Co-authored-by: Keegan Campbell <me@kfcampbell.com>

website/docs/r/repository_deploy_key.html.markdown

@@ -21,12 +21,17 @@ Further documentation on GitHub repository deploy keys:
 ## Example Usage
 
 ```hcl
-# Add a deploy key
+# Generate an ssh key using provider "hashicorp/tls"
+resource "tls_private_key" "example_repository_deploy_key" {
+  algorithm = "ED25519"
+}
+
+# Add the ssh key as a deploy key
 resource "github_repository_deploy_key" "example_repository_deploy_key" {
   title      = "Repository test key"
   repository = "test-repo"
-  key        = "ssh-rsa AAA..."
-  read_only  = "false"
+  key        = tls_private_key.example_repository_deploy_key.public_key_openssh
+  read_only  = true
 }
 ```