patch 8.2.0550: some changes in the libvterm upstream code

Problem:    Some changes in the libvterm upstream code.
Solution:   Include some changes.
diff --git a/src/version.c b/src/version.c
index ea8f84d..3ebee92 100644
--- a/src/version.c
+++ b/src/version.c
@@ -739,6 +739,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    550,
+/**/
     549,
 /**/
     548,