patch 8.1.0148: memory leak when using :tcl expr command

Problem:    Memory leak when using :tcl expr command.
Solution:   Free the result of expression evaluation. (Dominique Pelle,
            closes #3150)

src/version.c

@@ -789,6 +789,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    148,
 /**/
     147,
 /**/