workflows: add magiskboot

fix unable to boot in 6.6

Author: KOWX712

.github/workflows/build.yaml

@@ -32,6 +32,13 @@ jobs:
         mv module/bin/kptools-android module/bin/kptools
         mv module/bin/kpimg-linux module/bin/kpimg
 
+    - name: Download magiskboot binary
+      run: |
+        TAG=$(gh release list -R topjohnwu/Magisk -L 1 --json tagName --jq '.[0].tagName')
+        gh release download "$TAG" -R topjohnwu/Magisk -p "Magisk*.apk" -O magisk.apk
+        unzip -p magisk.apk 'lib/arm64-v8a/libmagiskboot.so' > module/bin/magiskboot
+        rm magisk.apk
+
     - name: build webroot
       run: |
         cd webui