patch 8.1.1021: pyeval() and py3eval() leak memory

Problem:    pyeval() and py3eval() leak memory.
Solution:   Do not increase the reference count twice. (Ozaki Kiichi,
            closes #4129)

src/version.c

@@ -779,6 +779,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1021,
 /**/
     1020,
 /**/