Remove armbian build

.github/workflows/build.yml

@@ -33,7 +33,7 @@ jobs:
     strategy:
       matrix:
         boards: [rock-5b]
-        build_systems: [rbuild, armbian]
+        build_systems: [rbuild]
         distros: [debian, ubuntu]
         flavors: [kde, xfce, cli]
         exclude:

README.md

@@ -11,9 +11,6 @@ Not all images are officially supported by Radxa. Some of them are only provided
 
 Currently the following images are provided:
 * Radxa [`rbuild`](https://github.com/radxa-repo/rbuild) images (currently testing)
-* [`Armbian`](https://github.com/armbian/build) images (**Unofficial build**)
-
-We provide **unofficial** Armbian images for evaluation purposes only. This is not a Radxa custom fork but built using unmodified upstream code. We do not support those images, and prefer to work with upstream directly to resolve the issues in their official releases.
 
 ## Is there any other options?