tfjson: Update Complete to a pointer value for older Terraform versions (#131)

Author: austinvalle

plan.go

@@ -66,7 +66,10 @@ type Plan struct {
 
 	// Complete indicates that all resources have successfully planned changes.
 	// This will be false if there are DeferredChanges or if the -target flag is used.
-	Complete bool `json:"complete,omitempty"`
+	//
+	// Complete was introduced in Terraform 1.8 and will be nil for all previous
+	// Terraform versions.
+	Complete *bool `json:"complete,omitempty"`
 
 	// The change operations for outputs within this plan.
 	OutputChanges map[string]*Change `json:"output_changes,omitempty"`