package/netsniff-ng: bump to version 0.6.6

package/netsniff-ng: bump to version 0.6.6

Update to new released version:

    https://github.com/netsniff-ng/netsniff-ng/releases/tag/v0.6.6

Changelog:

    implement rotating capture files in netsniff-ng
    fixed '--in -' to work again with STDIN in trafgen
    fixed -t 0 option to use sendto in trafgen
    checksum calculation for ICMP and TCP in astraceroute
    fix for reading mirrors from file in astraceroute
    use GZIP_ENV instead of GZIP in build system
    added error handling for mismatched address families in mausezahn

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