Update GitLab CI to FreeBSD 12.1

Since FreeBSD 12.1 is the current FreeBSD 12.x release, replace FreeBSD
12.0 GitLab CI jobs with their up-to-date counterparts.

(cherry picked from commit 4c68b56246)

.gitlab-ci.yml

@@ -944,28 +944,28 @@ unit:clang:freebsd11.3:amd64:
     - clang:freebsd11.3:amd64
   needs: ["clang:freebsd11.3:amd64"]
 
-# Jobs for Clang builds on FreeBSD 12.0 (amd64)
+# Jobs for Clang builds on FreeBSD 12.1 (amd64)
 
-clang:freebsd12.0:amd64:
+clang:freebsd12.1:amd64:
   variables:
     CFLAGS: "${CFLAGS_COMMON}"
     EXTRA_CONFIGURE: "--enable-dnstap"
   <<: *freebsd_amd64
   <<: *build_job
 
-system:clang:freebsd12.0:amd64:
+system:clang:freebsd12.1:amd64:
   <<: *freebsd_amd64
   <<: *system_test_job
   dependencies:
-    - clang:freebsd12.0:amd64
-  needs: ["clang:freebsd12.0:amd64"]
+    - clang:freebsd12.1:amd64
+  needs: ["clang:freebsd12.1:amd64"]
 
-unit:clang:freebsd12.0:amd64:
+unit:clang:freebsd12.1:amd64:
   <<: *freebsd_amd64
   <<: *unit_test_job
   dependencies:
-    - clang:freebsd12.0:amd64
-  needs: ["clang:freebsd12.0:amd64"]
+    - clang:freebsd12.1:amd64
+  needs: ["clang:freebsd12.1:amd64"]
 
 # Jobs for Clang builds on OpenBSD 6.6 (amd64)
 

PLATFORMS

@@ -15,14 +15,14 @@ offer support on a "best effort" basis for some.
 
 Regularly tested platforms
 
-As of Feb 2020, BIND 9.14 is fully supported and regularly tested on the
+As of Mar 2020, BIND 9.14 is fully supported and regularly tested on the
 following systems:
 
   * Debian 8, 9, 10
   * Ubuntu LTS 16.04, 18.04
   * Fedora 31
   * Red Hat Enterprise Linux / CentOS 6, 7, 8
-  * FreeBSD 11.3, 12.0
+  * FreeBSD 11.3, 12.1
   * OpenBSD 6.6
   * Alpine Linux
 

PLATFORMS.md

@@ -23,14 +23,14 @@ offer support on a "best effort" basis for some.
 
 ### Regularly tested platforms
 
-As of Feb 2020, BIND 9.14 is fully supported and regularly tested on the
+As of Mar 2020, BIND 9.14 is fully supported and regularly tested on the
 following systems:
 
 * Debian 8, 9, 10
 * Ubuntu LTS 16.04, 18.04
 * Fedora 31
 * Red Hat Enterprise Linux / CentOS 6, 7, 8
-* FreeBSD 11.3, 12.0
+* FreeBSD 11.3, 12.1
 * OpenBSD 6.6
 * Alpine Linux