patch 8.2.2066: Vim9: assignment with += doesn't work

Problem:    Vim9: assignment with += doesn't work.
Solution:   Do not see the "+" as an addition operator.
diff --git a/src/version.c b/src/version.c
index dac3d5c..b94f0df 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2066,
+/**/
     2065,
 /**/
     2064,