RELNOTES: add bugfixes

Note: They are added in the order that the issues were fixed/closed.

Note2: The issues were found through the following url:

https://github.com/netblue30/firejail/issues?q=is%3Aclosed+label%3Abug+-label%3Asecurity+closed%3A%3E2021-06-29+

The date used is the release date of 0.9.66, so in theory the query
should return every bug closed after that.  Security-related issues are
excluded because they will be added separately.

Note3: All issues other than netblue30#4328 were fixed before 0.9.68rc1.

Relates to netblue30#2758 netblue30#4235 netblue30#4328 netblue30#4387 netblue30#4395 netblue30#4460 netblue30#4467 netblue30#4558 netblue30#4560 netblue30#4586.

RELNOTES

@@ -15,6 +15,13 @@ firejail (0.9.68rc2) baseline; urgency=low
  * removed whitelist=yes/no in /etc/firejail/firejail.config
  * new condition: ALLOW_TRAY (#4510 #4599)
  * remove (some) environment variables with auth-tokens (#4157)
+ * bugfix: Error mounting tmpfs (MS_REMOUNT flag not being cleared) (#4387)
+ * bugfix: --build clears the environment (#4460 #4467)
+ * bugfix: Firejail does not work with a custom hosts file (#2758 #4560)
+ * bugfix: --tracelog and --trace override /etc/ld.so.preload (#4558 #4586)
+ * bugfix: Firejail rejects empty arguments (#4395)
+ * bugfix: firecfg does not work with symlinks (discord.desktop) (#4235)
+ * bugfix: Seccomp list output goes to stdout instead of stderr (#4328)
  * new includes: whitelist-run-common.inc (#4288), disable-X11.inc (#4462)
  * removed includes: disable-passwordmgr.inc (#4461)
  * new profiles: microsoft-edge-beta, clion-eap, lifeograph, zim