Update broken article link in README.

Signed-off-by: Marcus Müller <mueller_sourcecodinglib@baseband.digital>
diff --git a/README b/README
index 5110078..a9b1b05 100644
--- a/README
+++ b/README
@@ -29,7 +29,7 @@
 
 Mark Nelson <markn@ieee.org> wrote an article about zlib for the Jan.  1997
 issue of Dr.  Dobb's Journal; a copy of the article is available at
-http://marknelson.us/1997/01/01/zlib-engine/ .
+https://marknelson.us/posts/1997/01/01/zlib-engine.html .
 
 The changes made in version 1.2.13.1 are documented in the file ChangeLog.