chore: rename .yaml extensions to .yml for consistency

roles/proxmox-lxc-provision/tasks/check-exists.yml

@@ -0,0 +1,15 @@
+---
+- name: Query Proxmox for existing LXCs
+  community.proxmox.proxmox_lxc_info:
+    <<: "{{ proxmox_api_connection }}"
+  register: proxmox_lxcs
+
+- name: Check if LXC with hostname already exists
+  ansible.builtin.set_fact:
+    lxc_exists: >-
+      {{
+        proxmox_lxcs.proxmox_lxcs
+        | selectattr('name', 'equalto', lxc_hostname)
+        | list
+        | length > 0
+      }}