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)
diff --git a/src/version.c b/src/version.c
index 08a2e04..156e8dc 100644
--- a/src/version.c
+++ b/src/version.c
@@ -790,6 +790,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    148,
+/**/
     147,
 /**/
     146,