[gnome-build-meta] Update Pinebook Pro image

[Javier Jardón Cabezas <jjardon src gnome org>]

commit e5cf5bce410b8eb455aa6dced44646aa86f6b6cd
Author: Javier Jardón Cabezas <javierjc1982 gmail com>
Date:   Fri Sep 18 08:14:53 2020 +0000

    Update Pinebook Pro image

 Pinebook-Pro-image.md | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/Pinebook-Pro-image.md b/Pinebook-Pro-image.md
index 88ee6b9..0555f43 100644
--- a/Pinebook-Pro-image.md
+++ b/Pinebook-Pro-image.md
@@ -2,7 +2,9 @@
 
 The [Pinebook Pro](https://wiki.pine64.org/index.php/Pinebook_Pro) is a $200 arm 64 laptop from PINE64.
 
-Build `boards/pinebook-pro/image.bst`. Checkout the result.
+You will need to install BuildStream for build locally, check instructions at 
https://buildstream.build/install.html
+
+Build `boards/pinebook-pro/image.bst`. Checkout the result
 
 In the artifact, there will be a file named `disk.qcow2`. You can flash it to an sd card or an eMMC module 
using `qemu-img dd if=disk.qcow2 of=/dev/device-to-which-to-write`.