Upgrade to terraform >= 0.13

terraform.tf

@@ -1,6 +1,8 @@
 terraform {
-  required_version = ">= 0.12"
   required_providers {
-    digitalocean = ">= 1.18.0"
+    digitalocean = {
+      source  = "digitalocean/digitalocean"
+      version = ">= 2.0.2"
+    }
   }
 }

versions.tf

@@ -0,0 +1,3 @@
+terraform {
+  required_version = ">= 0.13"
+}