[debian] Use upstream MariaDB

This preserves the Debian-provided minor version - 10.5 in case
of Bullseye in Wallaby and Xena - and will be backported as
a fix to Victoria and Ussuri (where it will follow Buster and its
10.3).

Related-Bug: #1944410
Change-Id: I9704e5371a410cb1f69ec0367174e2b368961dc1

kolla/template/repos.yaml

@@ -70,6 +70,11 @@ debian:
     suite: "stable"
     component: "main"
     gpg_key: "elasticsearch.asc"
+  mariadb:
+    url: "http://downloads.mariadb.com/MariaDB/mariadb-10.5/repo/debian"
+    suite: "bullseye"
+    component: "main"
+    gpg_key: "mariadb.gpg"
   rabbitmq:
     url: "https://packagecloud.io/rabbitmq/rabbitmq-server/debian/"
     suite: "bullseye"
@@ -113,6 +118,11 @@ debian-aarch64:
     suite: "stable"
     component: "main"
     gpg_key: "elasticsearch.asc"
+  mariadb:
+    url: "http://downloads.mariadb.com/MariaDB/mariadb-10.5/repo/debian"
+    suite: "bullseye"
+    component: "main"
+    gpg_key: "mariadb.gpg"
   rabbitmq:
     url: "https://packagecloud.io/rabbitmq/rabbitmq-server/debian/"
     suite: "bullseye"

releasenotes/notes/debian-mariadb-upstream-75e05cbdaa013abe.yaml

@@ -0,0 +1,10 @@
+---
+upgrade:
+  - |
+    Debian now uses upstream MariaDB repos (thus following Ubuntu
+    images). This is done to avoid issues like the related one and
+    have an easy workaround of pinning to chosen MariaDB version if
+    need arises.
+    Operators may want to reflect this in their repo mirrors and
+    proxies.
+    `LP#1944410 <https://launchpad.net/bugs/1944410>`__