CI: bump gh-action-sdk to v3

Signed-off-by: Tianling Shen <[email protected]>

.github/workflows/multi-arch-test-build.yml

@@ -75,7 +75,7 @@ jobs:
           echo "PACKAGES=$PACKAGES" >> $GITHUB_ENV
 
       - name: Build
-        uses: immortalwrt/gh-action-sdk@v2
+        uses: immortalwrt/gh-action-sdk@v3
         env:
           ARCH: ${{ matrix.arch }}-${{ env.BRANCH }}
           FEEDNAME: packages_ci