prepare new version 5.3

Author: milamberspace

NOTICE

@@ -1,5 +1,5 @@
 Apache JMeter
-Copyright 1998-2019 The Apache Software Foundation
+Copyright 1998-2020 The Apache Software Foundation
 
 This product includes software developed at
 The Apache Software Foundation (http://www.apache.org/).

xdocs/download_jmeter.xml

@@ -18,7 +18,7 @@
 
 <!DOCTYPE document
 [
-<!ENTITY release '5.2.1'>
+<!ENTITY release '5.3'>
 <!ENTITY hellip   "&#x02026;" >
 ]>
 

xdocs/stylesheets/website-style.xsl

@@ -38,7 +38,7 @@
   <xsl:param name="cssdir" select="concat($relative-path, '/css')" />
   <xsl:param name="apidir" select="concat($relative-path, '/api')" />
   <xsl:param name="jakarta-site" select="'https://jakarta.apache.org'" />
-  <xsl:param name="year" select="'2019'" />
+  <xsl:param name="year" select="'2020'" />
   <xsl:param name="max-img-width" select="'600'" />
 
   <!-- Output method -->