patch 8.1.0621: terminal debugger does not handle unexpected debugger exit

Problem:    Terminal debugger does not handle unexpected debugger exit.
Solution:   Check for debugger job ended and close unused buffers. (Damien)
diff --git a/src/version.c b/src/version.c
index 333a98f..40c3c5a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -800,6 +800,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    621,
+/**/
     620,
 /**/
     619,