Update errata dates

Author: elistevens

docs/errata.html

@@ -140,7 +140,7 @@
 <div class="errata-body">
     <img style="float:left;width:150px;height:180px;border:1px solid black;margin:0px 10px 0px 0px;"
          src="./Stevens-DLPy-HI.png">
-    Errata: July 17, 2020
+    Errata: August 6, 2020
     <br/><br/>
     Thank you for purchasing
     <a href="https://www.manning.com/books/deep-learning-with-pytorch" target="_blank"><i>Deep
@@ -199,7 +199,8 @@ <h2>Page 258</h2>
 
 </div>
 <div class="copyright">
-    © 2018 Manning Publications Co. All rights reserved.
+    &copy; 2020 Manning Publications Co. All rights reserved.
+
 </div>