gitlab-ci: backfill missing Linux jobs

We're missing two Linux CI jobs in GitLab's CI that are present in
GitHub's CI. Backfill them to ensure that GitLab has the same test
coverage.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: pks-t

.gitlab-ci.yml

@@ -67,6 +67,12 @@ test:linux:
         image: alpine:latest
       - jobname: linux32
         image: i386/ubuntu:20.04
+      # A RHEL 8 compatible distro.  Supported until 2029-05-31.
+      - jobname: almalinux-8
+        image: almalinux:8
+      # Supported until 2026-08-31.
+      - jobname: debian-11
+        image: debian:11
   artifacts:
     paths:
       - t/failed-test-artifacts

ci/lib.sh

@@ -250,7 +250,7 @@ then
 		CI_OS_NAME=osx
 		JOBS=$(nproc)
 		;;
-	*,alpine:*|*,fedora:*|*,ubuntu:*|*,i386/ubuntu:*)
+	*,almalinux:*|*,alpine:*|*,debian:*|*,fedora:*|*,ubuntu:*|*,i386/ubuntu:*)
 		CI_OS_NAME=linux
 		JOBS=$(nproc)
 		;;