patch 8.2.2126: Ruby: missing function prototype

Problem:    Ruby: missing function prototype.
Solution:   Add the prototype.
diff --git a/src/version.c b/src/version.c
index 0a98c78..491ea90 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2126,
+/**/
     2125,
 /**/
     2124,