Point README installation to the AUR

Drop the xautolock-inhibit upgrade section, which only applied to the local package.

README.md

@@ -32,13 +32,18 @@ Formerly `xautolock-inhibit`, which supported only xautolock.
 
 ## Installation
 
-Build and install the package with the included PKGBUILD, which builds the signed release tag set in `pkgver`:
+Install [`xidle-inhibit`](https://aur.archlinux.org/packages/xidle-inhibit) from the AUR, for example with aurutils:
 
 ```
-makepkg -si
+aur sync xidle-inhibit
+pacman -S xidle-inhibit
 ```
 
-Or, with aurutils, build it into a local repository with `aur build` and install it with pacman.
+The PKGBUILD builds the signed release tag, so import the signing key first:
+
+```
+gpg --recv-keys 7E12BC1FF3B6EDB2CD8053EB981A2B2A3BBF5514
+```
 
 Then start it from your window manager's startup, after the locker. For xmonad with xautolock:
 
@@ -59,17 +64,6 @@ Without dimming, use `xset s 600 0` and `xss-lock -- slock`. Start xss-lock from
 
 The unit has no `[Install]` section on purpose. Enabling it at login would also start it in a desktop environment, or before X is up; starting it from the window manager limits it to that session. The user service manager needs `DISPLAY` (and `XAUTHORITY`) in its environment, which `/etc/X11/xinit/xinitrc.d/50-systemd-user.sh` sets up for `startx` sessions.
 
-### Upgrading from xautolock-inhibit
-
-The package replaces `xautolock-inhibit`. After upgrading, change the `systemctl --user start` line in your window manager's startup, then switch the running daemon:
-
-```
-systemctl --user stop xautolock-inhibit
-systemctl --user start xidle-inhibit
-```
-
-Requests held by the old daemon are taken over if the new one starts within `--restore-window`.
-
 ## Configuration
 
 The backend is set in `~/.config/xidle-inhibit/config` (`$XDG_CONFIG_HOME`):