Fix #988893, CVE-2021-28651

See merge request !17

    purge.
  * Clarify on postrm script the the debhelper code was put manually.

    Fixes: CVE-2020-25097. Closes: #985068.

get back to the old postrm files and build depend on that version of debhelper
or higher.

  * Increase debhelper build dependency to 12.8 as we need that from -5.
  * Add NEWS note on the problem with purge on previous versions.

This involves using squid.init instead of squid.rc, so i had it renamed.
Also I removed a log that I had pushed while sleeping.

Fix release on NEWS.

Update to upstream version '4.13'
with Debian dir ca75b8b9f61ec058deb3afb4856a2849a3ef3a39

Update to upstream version '4.12'
with Debian dir 492c2165388d1fc50217af2013cca33f464543ca

Squid cleanup postinst

See merge request squid-team/squid!13

squid 2.7 is long, long gone, so it should be safe to drop the
postinst code to make sure that /etc/squid/squid.conf was properly
upgraded.

When installing/upgrading squid, the service is being restarted
manually in the postinst script, which can break installations that
have the squid apparmor enabled because it will try to restart the
service before reloading the apparmor profile.

There is no reason to restart squid manually, since the restart will
be automatically performed later.