backup-and-update-system: we no longer use yay

.bin/backup-and-update-system

@@ -10,7 +10,7 @@ git --git-dir=$HOME/.cfg/ --work-tree=$HOME push
 # Fetch a fresh copy of all locally cloned git repos
 for dir in $(find /home/kunsi/git -mindepth 1 -maxdepth 1 -type d)
 do
-    git --git-dir=$dir/.git --work-tree=$dir fetch || true
+    git -C "$dir" fetch || true
 done
 
 # Do a backup.
@@ -36,4 +36,4 @@ rsync -zaAP --numeric-ids --delete --relative \
     "/home/kunsi" "kunsi-t470@home.nas":backups/
 
 # Do updates
-yay -Syu
+sudo pacman -Syu --noconfirm