updated tasks so they are only run once

tasks/pkgs/zig.yml

@@ -1,5 +1,17 @@
 # vim: set filetype=yaml.ansible :
 ---
-- name: Append to pkgs
-  ansible.builtin.set_fact:
-    pkg_archive: "{{ pkg_archive + ['zig'] }}"
+- name: Add zig
+  when:
+    - zig_configured is undefined
+  block:
+    - name: Load zig config
+      ansible.builtin.include_tasks:
+        file: config/zig.yml
+
+    - name: Append to pkgs
+      ansible.builtin.set_fact:
+        pkg_archive: "{{ pkg_archive + ['zig'] }}"
+
+    - name: Set zig_configured
+      ansible.builtin.set_fact:
+        zig_configured: true