patch 9.0.1945: Vim9: missing support for ro-vars in interface

Problem:  Vim9: missing support for ro-vars in interface
Solution: Support only read-only object variables in an interface,
          add additional checks when parsing class definitions.

closes: #13183
cloess: #13184
cloess: #13185.
closes: #13188

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>
diff --git a/src/version.c b/src/version.c
index ddf9a74..aef4b1a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1945,
+/**/
     1944,
 /**/
     1943,