Add s390x architecture support

* Update debug.yml

Signed-off-by: 永雏塔菲 <108621198+taffychan@users.noreply.github.com>

.github/workflows/debug.yml

@@ -149,6 +149,9 @@ jobs:
           - name: linux-mips64el
             goos: linux
             goarch: mips64le
+          - name: linux-s390x
+            goos: linux
+            goarch: s390x
           # darwin
           - name: darwin-amd64
             goos: darwin
@@ -213,4 +216,4 @@ jobs:
         uses: actions/upload-artifact@v2
         with:
           name: sing-box-${{ matrix.name }}
-          path: sing-box*
+          path: sing-box*