change task and meta

meta/main.yml

@@ -8,4 +8,5 @@ galaxy_info:
   galaxy_tags:
     - debian
     - ipv6
-dependencies: []
+dependencies:
+  - ansible.posix.sysctl

tasks/main.yml

@@ -1,9 +1,6 @@
 ---
-- name: set sysctl
-  ansible.builtin.lineinfile:
-    create: yes
-    path: /etc/sysctl.conf
-    line: "net.ipv6.conf.all.disable_ipv6 = 1"
-
-- name: accept sysctl
-  ansible.builtin.command: sysctl -p
+- name: set disable_ipv6 in sysctl
+  ansible.posix.sysctl:
+    name: net.ipv6.conf.all.disable_ipv6
+    value: '1'
+    state: present