C++: Fix strncpy reference link (the old link was broken).

Author: geoffw0

cpp/ql/src/Likely Bugs/Memory Management/StrncpyFlippedArgs.qhelp

@@ -25,7 +25,7 @@ not the source buffer.</p>
 
 <references>
 
-<li>cplusplus.com: <a href="http://www.cplusplus.com/reference/clibrary/cstring/strncpy/">strncpy</a>.</li>
+<li>cplusplus.com: <a href="https://cplusplus.com/reference/cstring/strncpy/">strncpy</a>.</li>
 <li>
   I. Gerg. <em>An Overview and Example of the Buffer-Overflow Exploit</em>. IANewsletter vol 7 no 4. 2005.
 </li>