chore(ci): pin mariadb container to 10.7 image tag (#3913)

MariaDB latest only works on newer versions of Docker (see MariaDB/mariadb-docker#434).

So we are pinning to mariadb:10.7 for now to ensure consistent startup of the container in CircleCI.

(cherry picked from commit 27a55df)

docker-compose.yml

@@ -26,7 +26,7 @@ services:
         ports:
             - "127.0.0.1:5432:5432"
     mariadb:
-        image: mariadb
+        image: mariadb:10.7
         environment:
             - MYSQL_ROOT_PASSWORD=example
             - MYSQL_DATABASE=test