Update reference file loader help text to GRCh38/hg38

mutalyzer/website/templates/reference-loader.html

@@ -61,7 +61,7 @@ sequence (maximum size is {{ max_file_size }} megabytes):
           <b>Note:</b> This uses
           the <a href="http://www.ncbi.nlm.nih.gov/sites/gquery">NCBI
           Entrez</a> search engine and is therefore based on the current
-          Entrez assembly for the given organism (GRCh37/hg19 for human).
+          Entrez assembly for the given organism (GRCh38/hg38 for human).
             <table>
                 <tr>
               <td>Gene symbol</td>