Upgrade Http Components Core and Client to 5.0

Notable changes and features included in the 5.0 series are:

• Support for the HTTP/2 protocol and conformance to requirements and
  recommendations of the latest HTTP/2 protocol specification documents
  (RFC 7540, RFC 7541.)

Supported features:

• • HPACK header compression
  • Stream multiplexing (client and server)
  • Flow control
  • Response push
  • Message trailers
  • Expect-continue handshake
  • Connection validation (ping)
  • Application-layer protocol negotiation (ALPN)
  • TLS 1.2 security features

• Improved conformance to requirements and recommendations of the
  latest HTTP/1.1 protocol specification documents (RFC 7230, RFC 7231)

• New connection pool implementation with lax connection limit
  guarantees and better performance under higher concurrency due to
  absence of a global pool lock.

• Support for Reactive Streams API http://www.reactive-streams.org/

• Package name space changed to 'org.apache.hc.client5'.

• Maven group id changed to 'org.apache.httpcomponents.client5'.

HttpClient 5.0 releases can be co-located with earlier major versions
on the same classpath due to the change in package names and Maven
module coordinates.

Download - <http://hc.apache.org/downloads.cgi>
Release notes - <
https://www.apache.org/dist/httpcomponents/httpclient/RELEASE_NOTES-5.0.x.txt