security/clamav-lts: Add new port

* Add Long Term Support release of ClamAV
* Add CONFLICTS_INSTALL to security/clamav
* Add entry to UPDATING that explains
  - Upstream changed their end-of-life policy and LTS release is
    introduced
  - How to switch from regular release (security/clamav) to LTS
    release (security/clamav-lts)

Note about setting PORTEPOCH

In general new port should not set PORTEPOCH. But in this case it
should be set with following reason.

1. Recently upstream changed their end-of-life policy as following.
  - Regular feature release (= 0.xyz.0 release) is released more
    frequently, and life time of each feature release is shortened to
    about 4 months.
  - To compensate for the short lifetime of regular feature release,
    Long Term Support feature release is introduced and its life time
    is about 3 years.
2. First LTS starts with version 0.103.3 and it is same as current
   version of security/clamav.
3. Because of short lifetime of regular feature release, it is
   probable that not a few users of security/clamav want to switch to
   security/clamav-lts after the latter is connected (and the former
   is updated to 0.104.0).
3. For such users the entry is added to UPDATING about how to switch
   from security/clamav to security/clamav-lts. And binary package
   user is suggested to execute
   `pkg set -o security/clamav:security/clamav-lts`. This command
   changes the origin of already installed clamav packages. So user
   can switch to LTS version without reinstalling.
4. But if PORTEPOCH isn't set in security/clamav-lts, binary package
   user who executed above command will notice that version of
   installed package (0.103.3,1) succeeds to current version of
   security/clamav-lts (0.103.3). The situation doesn't change after
   new patch release (0.103.4 for example) is released and it causes
   the problem that installed package isn't properly upgraded with
   `pkg upgrade`.
5. So PORTEPOCH is set in  security/clamav-lts to prevent binary
   package user from suffering from such problem.

1 files changed, 28 insertions, 0 deletions

diff --git a/UPDATING b/UPDATING
index 7aa749aafd2e..509879b0cdd4 100644
--- a/UPDATING
+++ b/UPDATING
@@ -5,6 +5,34 @@ they are unavoidable.
 You should get into the habit of checking this file for changes each time
 you update your ports collection, before attempting any port upgrades.
 
+20211007:
+  AFFECTS: user of security/clamav
+  AUTHOR: yasu@FreeBSD.org
+
+  Upstream changed end-of-life policy and introduced long time support
+  (LTS) feature release.
+
+  * LTS feature release will be identified approximately every two
+    years and supported for at least three years from the initial
+    publication date of that LTS feature version.
+  * Regular (non-LTS) feature releases will be supported for at least
+    four months from the initial publication date of the next feature
+    release or until the feature release after that is published.
+
+  According to it new port security/clamav-lts is added for users who
+  want to use LTS version of ClamAV.
+
+  Users wanting to switch to LTS version can replace security/clamav
+  with security/clamav-lts with one of following commands.
+
+  If you use pkg with binary packages:
+    # pkg set -o security/clamav:security/clamav-lts
+    # pkg upgrade
+  If you use portmaster:
+    # portmaster -o security/clamav-lts security/clamav
+  If you use portupgrade:
+    # portupgrade -o security/clamav-lts security/clamav
+
 20211006:
 AFFECTS: users of misc/freebsd-doc-*
 AUTHOR: blackend@FreeBSD.org