Using arc-gtk-theme instead of gtk-theme-arc-git

* Avoids (undocumented) gtk3 build-time dependency
* The community package is based on the new soft-fork of the main repo
  * Link for details: https://github.com/horst3180/arc-theme/issues/840

.linux_items/packages/aur

@@ -1,6 +1,5 @@
 aic94xx-firmware
 bash-pipes
-gtk-theme-arc-git
 hfsprogs
 i3lock-fancy-git
 mprime

.linux_items/packages/live

@@ -1,6 +1,7 @@
 aic94xx-firmware
 alsa-utils
 antiword
+arc-gtk-theme
 bash-pipes
 bc
 bluez
@@ -22,7 +23,6 @@ firefox
 gnome-keyring
 gparted
 gsmartcontrol
-gtk-theme-arc-git
 hardinfo
 hexedit
 hfsprogs