Fix srcds_run crash with error message 'cat: hlds.{PID}.pid: No such file or directory'

Multiple causes:

• Pin to 18.04 not latest. Latest auto upgraded to Ubuntu 20.04. 20.04
  currently segfaults steamcmd.
• Targeted pruning of /var/lib/dpkg instead of wiping. amd64/i386 repos now
  enabled on Docker startup, enabling updates for both.
• Add explicit requirements for GDB and c++6; enabling -debug option
  for srcds_run which prevents PID error and auto reboot every 10 seconds.
  See: https://forums.alliedmods.net/showthread.php?t=300118
• wine 5.x added requirement of libfaudio0, but not included for version of
  Ubuntu < 19.10. Install these manually.

Changes:

• steam -> stable.
• winehq -> latest.