ci: fix archlinux builds

The "xorg-server-xwayland" package has become "xorg-xwayland" in Arch.
Our egl requirement was previously satisfied by xorg-server-xwayland's
dependency on libgl, which "xorg-xwayland" does not have. So add the
libegl dependency as well.

.builds/archlinux.yml

@@ -3,6 +3,7 @@ packages:
   - cairo
   - gdk-pixbuf2
   - json-c
+  - libegl
   - libinput
   - libxcb
   - libxkbcommon
@@ -12,7 +13,7 @@ packages:
   - wayland
   - wayland-protocols
   - xcb-util-image
-  - xorg-server-xwayland
+  - xorg-xwayland
 sources:
   - https://github.com/swaywm/sway
   - https://github.com/swaywm/wlroots