patch 9.0.0295: GUI drop files test sometimes fails

Problem:    GUI drop files test sometimes fails.
Solution:   Mark the test as flaky.
diff --git a/src/version.c b/src/version.c
index afb61e0..280fcff 100644
--- a/src/version.c
+++ b/src/version.c
@@ -708,6 +708,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    295,
+/**/
     294,
 /**/
     293,