* security bug reported by Austin Morton:
    Seccomp filters are copied into /run/firejail/mnt, and are writable
    within the jail. A malicious process can modify files from inside the
    jail. Processes that are later joined to the jail will not have seccomp
    filters applied.
  * memory-deny-write-execute now also blocks memfd_create
  * add private-cwd option to control working directory within jail
  * blocking system D-Bus socket with --nodbus
  * bringing back Centos 6 support
  * drop support for flatpak/snap packages
  * new profiles: crow, nyx, mypaint, celluoid, nano, transgui, mpdris2
  * new profiles: sysprof, simplescreenrecorder, geekbench, xfce4-mixer
  * new profiles: pavucontrol, d-feet, seahorse, secret-tool, gnome-keyring
  * new profiles: regextester, hardinfo, gnome-system-log, gnome-nettool
  * new profiles: netactview, redshift, devhelp, assogiate, subdownloader
  * new profiles: font-manager, exfalso, gconf-editor, dconf-editor
  * new profiles: sysprof-cli, seahorse-tool, secret-tool, dconf, gsettings
  * new profiles: code-oss, pragha, Maelstrom, ostrichriders, bzflag
  * new profiles: freeciv, lincity-ng, megaglest, openttd, crawl, crawl-tiles
  * new profiles: teeworlds, torcs, tremulous, warsow, lugaru, manaplus
  * new profiles: pioneer, scorched3d, widelands, freemind, kid3, kid3-qt
  * new profiles: kid3-cli, nomacs, freecol, opencity, openclonk, slashem
  * new profiles: vultureseye, vulturesclaw, anki, cheese, utox, mp3splt
  * new profiles: oggsplt, flacsplt, gramps, newsboat, freeoffice-planmaker
  * new profiles: autokey-gtk, autokey-qt, autokey-run, autokey-shell
  * new profiles: freeoffice-presentations, freeoffice-textmaker, mp3wrap
  * new profiles: inkview, meteo-qt, mp3splt-gtk, ktouch, yelp, cantata