Sync and update pacman first

Before executing any steps pacman needs to be initiated. Especially
important on new systems that haven't had a pacman command run yet.

playbooks/manjaro.yaml

@@ -8,6 +8,13 @@
     swap_file_size_mb: 4096
 
   tasks:
+  # Sync and update Pacman
+  - name: Sync and update Pacman
+    community.general.pacman:
+      update_cache: yes
+      upgrade: yes
+    become: yes
+
   # SSH
   - name: Ensure openssh installed
     community.general.pacman: