package/netsniff-ng: bump to version 0.6.7

package/netsniff-ng: bump to version 0.6.7

1. trafgen: reset errno before calling sscanf in str2mac (@troglobit, #213)
2. ifpps: fix iface stat parsing if interface name contains uppercase
   characters (@bganne, #215)
3. mausezahn: fix display of missing argument error (@micrictor, #217)
4. mausezahn: support -R to set packet priority (@pmachata)
5. netsniff-ng: handle various malformed packets in protocol dissectors
   (@nathaniellives, #221)

Signed-off-by: Vadym Kochan <vadim4j@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>