Checkout submodules

Signed-off-by: Huy Do <huydhn@gmail.com>

Author: huydhn

.github/workflows/flash_attention.yml

@@ -24,8 +24,9 @@ jobs:
       - name: Checkout Flash Attention repository
         uses: actions/checkout@v4
         with:
-          repository: 'Dao-AILab/flash-attention'
-          path: 'fa4'
+          repository: Dao-AILab/flash-attention
+          path: fa4
+          submodules: recursive
 
       - name: Setup GPU flags for docker run
         run: |