feat: Add function to support SSH keys based on file or text (#3)

README.md

@@ -10,6 +10,8 @@ Terraform module to manage the Hetzner Cloud resource (hcloud_ssh_key).
 
 Copy and paste into your Terraform configuration, insert the variables and run ```terraform init```:
 
+**Provide SSH key as file:**
+
 ```hcl
 module "hcloud-ssh_key" {
   source = "dhoppeIT/ssh_key/hcloud"
@@ -19,6 +21,17 @@ module "hcloud-ssh_key" {
 }
 ```
 
+**Provide SSH key as text:**
+
+```hcl
+module "hcloud-ssh_key" {
+  source = "dhoppeIT/ssh_key/hcloud"
+
+  name       = "terraform"
+  public_key = "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAACAQC3euXiX6jFStmjcDzW4dHZSdSUuip3cGu62Fhh0+zdILdzvyoMwqeuuuWova+ltZfeAgZOd6n0QKOhs2eTj6eEfTyIpmmCQgosu1GyQKQ8oHcBqDV+atrc2MQRhZPIZgVXn4CL8IldlEjYoGI6zreBY1uEhUoGC79bt9Eqtmxr1M8xQmJ1ZVI8kzDLax31vckuWnO3PlaUyT5VPBC/XPLdZ3PodX7J2CQ0MwlHzG1qFxrp1XonYpV1Rbfb9Vj4Wu27Md7RETSOZq7wlsgEC7MBTb6guFuz4tL5CfiHO3YhZEmtWi5UL7YMuP4pD+mGU3nKcQOsOYNpuzV5p7NZANv+i40BtSJiQCWbzrPAOvj8Pn5lk/7aE3uVRHAWpIwGJ3HAof9VS5EoM2oq6dwAM8bK/XBz77pOdyHv+89o3Rc/WzhBs5wSMHUd54SQZ4STEERmi/GWUcfYi30s01W2SmH3H02NI8iPfNvDma858CfwDELNJnE7rphG1INQSZArSzpTZpoHFPZ0pIvG7mFMKeYmjizV8W9TwS+IpuLR6Cm3plUIhQhAzbyeVVKAU+66DtywIKdJm20Y94joVQD3KOGlxUrqKwyTZAOkknR7/yKiQfgritlRKVdLHyW/znBKCHskwqp9WgXBP6q4YvfM3muWK+guj+wi+9CtjNUYT+tkRQ== Terraform"
+}
+```
+
 <!--- BEGIN_TF_DOCS --->
 ## Requirements
 

main.tf

@@ -1,4 +1,4 @@
 resource "hcloud_ssh_key" "default" {
   name       = var.name
-  public_key = file("${var.public_key}")
+  public_key = fileexists("${var.public_key}") ? file("${var.public_key}") : var.public_key
 }