Drop Debian buster from the CI

The Debian buster is officially EoL and in LTS mode, so we can drop it
to stabilize the CI.

(cherry picked from commit 7238c85c88)

.gitlab-ci.yml

@@ -132,10 +132,6 @@ 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
@@ -855,33 +851,6 @@ gcc:tarball:nosphinx:
     - job: tarball-create
       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_pipelines_schedules_tags_triggers_web_triggering_rules
-
-system:gcc:buster:amd64:
-  <<: *debian_buster_amd64_image
-  <<: *system_test_job
-  <<: *api_pipelines_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_pipelines_schedules_tags_triggers_web_triggering_rules
-  needs:
-    - job: gcc:buster:amd64
-      artifacts: true
-
 # Jobs for regular GCC builds on Debian 12 "bookworm" (amd64)
 
 gcc:bookworm:amd64:

doc/arm/platforms.inc.rst

@@ -45,7 +45,7 @@ Regularly Tested Platforms
 Current versions of BIND 9 are fully supported and regularly tested on the
 following systems:
 
--  Debian 10, 11, 12
+-  Debian 11, 12
 -  Ubuntu LTS 20.04, 22.04
 -  Fedora 39
 -  Red Hat Enterprise Linux / CentOS / Oracle Linux 7, 8, 9
@@ -91,7 +91,7 @@ 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
 
 -  Less common CPU architectures (i386, i686, mips, mipsel, sparc, ppc, and others)