ci: do not create not firmware build when readme has been updated

Author: tobiasbueschel

.github/workflows/build.yml

@@ -4,8 +4,10 @@ on:
   push:
     paths-ignore:
       - "keymap-drawer/**"
+      - "README.md"
+      - "keymap_drawer.config.yaml"
+      - ".gitignore"
 
 jobs:
   build:
     uses: zmkfirmware/zmk/.github/workflows/build-user-config.yml@main
-