HTTPCLIENT-2295 Fix links to Core Javadoc

Author: kwin

pom.xml

@@ -227,8 +227,8 @@
  <artifactId>maven-javadoc-plugin</artifactId>
  <configuration>
  <links>
- <link>https://hc.apache.org/httpcomponents-core-5.0.x/httpcore5/apidocs/</link>
- <link>https://hc.apache.org/httpcomponents-core-5.0.x/httpcore5-h2/apidocs/</link>
+ <link>https://hc.apache.org/httpcomponents-core-5.2.x/current/httpcore5/apidocs/</link>
+ <link>https://hc.apache.org/httpcomponents-core-5.2.x/current/httpcore5-h2/apidocs/</link>
  <link>${project.url}/httpclient5/apidocs/</link>
  </links>
  </configuration>