patch 8.1.0975: using STRNCPY() wrongly. Warning for uninitialized variable

Problem:    Using STRNCPY() wrongly. Warning for uninitialized variable.
Solution:   Use mch_memmove(). Initialize variable. (Yasuhiro Matsumoto,
            closes #3979)
diff --git a/src/version.c b/src/version.c
index cd2554a..0980420 100644
--- a/src/version.c
+++ b/src/version.c
@@ -780,6 +780,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    975,
+/**/
     974,
 /**/
     973,