vendor: update buildkit to master@9624ab4

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

vendor/github.com/moby/buildkit/util/system/atime_windows.go

@@ -0,0 +1,17 @@
+package system
+
+import (
+	"fmt"
+	iofs "io/fs"
+	"syscall"
+	"time"
+)
+
+func Atime(st iofs.FileInfo) (time.Time, error) {
+	stSys, ok := st.Sys().(*syscall.Win32FileAttributeData)
+	if !ok {
+		return time.Time{}, fmt.Errorf("expected st.Sys() to be *syscall.Win32FileAttributeData, got %T", st.Sys())
+	}
+	// ref: https://github.com/golang/go/blob/go1.19.2/src/os/types_windows.go#L230
+	return time.Unix(0, stSys.LastAccessTime.Nanoseconds()), nil
+}