Lock ZMK to v0.3.0

Author: duckyb

.github/workflows/build.yml

@@ -2,4 +2,4 @@ on: [push, pull_request, workflow_dispatch]
 
 jobs:
   build:
-    uses: zmkfirmware/zmk/.github/workflows/build-user-config.yml@main
+    uses: zmkfirmware/zmk/.github/workflows/build-user-config.yml@v0.3.0

config/west.yml

@@ -15,7 +15,7 @@ manifest:
   projects:
     - name: zmk
       remote: zmkfirmware
-      revision: main
+      revision: v0.3.0
       import: app/west.yml
     - name: urchin-zmk-module
       remote: duckyb