Drop Debian buster from the CI

The Debian buster is official EOL and in the LTS mode, so we can drop
this for the next stable BIND 9 release.

.gitlab-ci.yml

@@ -122,10 +122,6 @@ stages:
 
 # Debian
 
-.debian-buster-amd64: &debian_buster_amd64_image
-  image: "$CI_REGISTRY_IMAGE:debian-buster-amd64"
-  <<: *linux_amd64
-
 .debian-bullseye-amd64: &debian_bullseye_amd64_image
   image: "$CI_REGISTRY_IMAGE:debian-bullseye-amd64"
   <<: *linux_amd64
@@ -657,33 +653,6 @@ unit:gcc:oraclelinux9:amd64:
     - job: gcc:oraclelinux9:amd64
       artifacts: true
 
-# Jobs for regular GCC builds on Debian 10 "buster" (amd64)
-
-gcc:buster:amd64:
-  variables:
-    CC: gcc
-    CFLAGS: "${CFLAGS_COMMON}"
-    EXTRA_CONFIGURE: "--with-libidn2"
-  <<: *debian_buster_amd64_image
-  <<: *build_job
-  <<: *api_schedules_tags_triggers_web_triggering_rules
-
-system:gcc:buster:amd64:
-  <<: *debian_buster_amd64_image
-  <<: *system_test_job
-  <<: *api_schedules_tags_triggers_web_triggering_rules
-  needs:
-    - job: gcc:buster:amd64
-      artifacts: true
-
-unit:gcc:buster:amd64:
-  <<: *debian_buster_amd64_image
-  <<: *unit_test_job
-  <<: *api_schedules_tags_triggers_web_triggering_rules
-  needs:
-    - job: gcc:buster:amd64
-      artifacts: true
-
 # Jobs for regular GCC builds on Debian 11 "bullseye" (amd64)
 # (The second unit test job also executes unstable unit tests.)
 

doc/arm/platforms.inc.rst

@@ -45,7 +45,7 @@ Regularly Tested Platforms
 As of August 2022, current versions of BIND 9 are fully supported and regularly tested on the
 following systems:
 
--  Debian 10, 11
+-  Debian 11
 -  Ubuntu LTS 18.04, 20.04, 22.04
 -  Fedora 36
 -  Red Hat Enterprise Linux / CentOS / Oracle Linux 7, 8, 9
@@ -92,7 +92,7 @@ supported platforms.
 
    -  Ubuntu 14.04, 16.04 (Ubuntu ESM releases are not supported)
    -  CentOS 6
-   -  Debian 8 Jessie, 9 Stretch
+   -  Debian 8 Jessie, 9 Stretch, 10 Buster
    -  FreeBSD 10.x, 11.x
 
 Unsupported Platforms