Use "launchctl bootstrap" on MacOS

In the most recent MacOS releases, `launchctl load` is marked as "Legacy":

```
LEGACY SUBCOMMANDS
Legacy subcommands select the target domain based on whether they are executed as root or not. When executed as root,
they target the system domain.

load | unload [-wF] [-S sessiontype] [-D searchpath] paths ...
Recommended alternative subcommands: bootstrap | bootout | enable | disable
...
```

So it might be a good idea to switch to `launchctl boostrap` instead.