update broken LLNL image link

Author: hauten

_includes/head.html

@@ -24,7 +24,7 @@
 <meta name="twitter:site" content="@llnl_opensource" />
 <meta name="twitter:title" content="LLNL Software Catalog" />
 <meta name="twitter:description" content="Software available from LLNL." />
-<meta name="twitter:image" content="https://cdn.llnl.gov/onelab/0.1.1/images/llnl-logo-blue-128x128.jpg" aria-label="LLNL logo" />
+<meta name="twitter:image" content="https://cdn.llnl.gov/onelab/latest/images/llnl-logo-400x400.png" aria-label="LLNL logo" />
 
 <meta name="google-site-verification" content="477TVoInt3HiUgSl_hU4rb5_JrgNMKK5Rl-KPMUClpQ" />