Replace deprecated set-output / save the brainux version into the vfat partition

.github/workflows/build.yml

@@ -259,11 +259,15 @@ jobs:
         run: make brainux
       - name: Build bsd-ce
         run: make -C nkbin_maker bsd-ce
-      - name: Generate image name
+      - name: Generate version string and image name
         id: image_name
-        run: echo ::set-output name=name::sdimage-${GITHUB_REF/refs\/*s\//}
+        run: |
+          echo "name=sdimage-${GITHUB_REF/refs\/*s\//}" >> $GITHUB_OUTPUT
+          echo "version=${GITHUB_REF/refs\/*s\//}" >> $GITHUB_OUTPUT
       - name: Build SD image
         run: make image/sd.img && mv image/sd.img ${{ steps.image_name.outputs.name }}.img
+        env:
+          BRAINUX_VERSION: ${{ steps.image_name.outputs.version }}
       - name: Compress
         run: zip ${{ steps.image_name.outputs.name }}.zip ${{ steps.image_name.outputs.name }}.img
       - name: Upload the image