Add xz-utils dependency

.gitlab-ci.yml

@@ -17,7 +17,7 @@ build-zynthbox-image-armhf:
 
     # Update and install dependencies
     - apt-get update
-    - apt-get install -y coreutils p7zip-full qemu-user-static sudo git wget python3 lsof fdisk
+    - apt-get install -y coreutils p7zip-full qemu-user-static sudo git wget python3 lsof fdisk xz-utils
 
     # Clone repositories required to generate image
     - git clone https://github.com/zynthbox/CustomPiOS.git