[ANN] packetgen 2.6.0 released

packetgen 2.6.0 has been released.

* home: <https://github.com/sdaubert/packetgen>
* bugs: <https://github.com/sdaubert/packetgen/issues>
* doc: <https://github.com/sdaubert/packetgen/wiki>

PacketGen provides simple ways to generate, send and capture network
packets.

Known protocols are: Ethernet, Dot11, Dot1x, ARP, IP, IPv6, GRE, ICMP,
IGMP, ICMPv6, MLD, MLDv2, OSPFv2, OSPFv3, UDP, TCP, SNMP, ESP, DNS, IKE,
EAP, BOOTP, DHCP, TFTP, NetBIOS, HTTP and MDNS.

Changes:

### 2.6.0 / 2018-07-04

* Add support for mDNS protocol.
* Header::SNMP#initialize now supports 2 more options:
  * one to set PDU to use,
  * one to set PDU content from a hash.
* Fixed bugs:
  * HTTP::Request might raise when parsing a HTTP request due to some
character set incoherency. Fixed by picatz (thank you).