Add outputs.files task to plan

Signed-off-by: Helder Correia <174525+helderco@users.noreply.github.com>

tests/plan/outputs/files/default_permissions.cue

@@ -0,0 +1,10 @@
+package main
+
+import "dagger.io/dagger"
+
+dagger.#Plan & {
+	outputs: files: test: {
+		contents: "foobar"
+		dest:     "./test"
+	}
+}