use build matrix with reusable build config

build.yaml

@@ -1 +1,17 @@
-board: [ "le_chiff_ble" ]
+matrix:
+  # List the firmware to build here. Each item use the following properties.
+  #  board: (required) the board to build.
+  #  shield: (optional) the shield to build. Omit for a standalone board.
+  #  cmake-args: (optional) extra arguments to pass to CMake as a string.
+  include:
+    - board: le_chiff_ble
+      artifact_prefix: schiffer_bleu
+      keyboard_name: "schiffer bleu"
+
+    - board: le_chiff_ble
+      artifact_prefix: schiffer_pink
+      keyboard_name: "schiffer pink"
+
+    - board: le_chiff_ble
+      artifact_prefix: schiffer_gelb
+      keyboard_name: "schiffer gelb"