systemd service: fix start up ordering

[gdamjan]

the service needs to have After=wayland-session.target otherwise it'll
be started in parallel to the compositor which might not be fully
configured.

ps. sorry I overlooked this setting when I was sending the previous pull request.

[Alexays]

Thanks!

[freed00m]

Where is the wayland-session.target coming from, who provides it?

Only what I have is graphical-session.target

Edit: I still cannot figure it how to make it start after sway.service (I've even created a --user sway-session.target)

This is my current waybar unit that not work, will update when I'll find solution.

[Unit]
Description=Highly customizable Wayland bar for Sway and Wlroots based compositors.
Documentation=https://github.com/Alexays/Waybar/wiki/
#BindsTo=sway-session.target
Requires=graphical-session.target
PartOf=graphical-session.target

[Service]
Type=simple
# 2 second should be enough after login
#ExecStartPre=sleep 2 
ExecStart=/usr/bin/bash -c "export SWAYSOCK=/run/user/$(id -u)/sway-ipc.$(id -u).$(pgrep -x sway).sock && /usr/bin/waybar"

[Install]
WantedBy=sway-session.target