github: add missing backslash

Signed-off-by: Zhongteng Gui <dragon-archer@outlook.com>
Signed-off-by: LIU Hao <lh_mouse@126.com>

.github/workflows/build.yml

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index addcd51..9fe2fa8 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -784,7 +784,7 @@
           mkdir build
           cd build
           ../configure \
-              --disable-dependency-tracking
+              --disable-dependency-tracking \
               --prefix=/gcc-mingw/${{matrix.arch}}-w64-mingw32 \
               --host=${{matrix.arch}}-w64-mingw32 \
               --enable-silent-rules \