Notifies of available updates.

`pacman-update-count.sh` -- run as root to update available count.

`notify-updates` -- run to notify of available updates (gets value stored by `pacman-update-count.sh`).

```sh
# list options:

notify-updates --help
```

## TODO

* `notify-updates` triggered to run after `pacman-update-count`
* config file for `notify-updates`
* `update.sh` script