fix python artifact build
diff --git a/build.yaml b/build.yaml
index 95f6788..18fc37f 100644
--- a/build.yaml
+++ b/build.yaml
@@ -316,6 +316,7 @@
   - src/core/lib/iomgr/ev_epollsig_linux.c
   - src/core/lib/iomgr/ev_poll_posix.c
   - src/core/lib/iomgr/ev_posix.c
+  - src/core/lib/iomgr/ev_windows.c
   - src/core/lib/iomgr/exec_ctx.c
   - src/core/lib/iomgr/executor.c
   - src/core/lib/iomgr/iocp_windows.c