[DBBackup] Change packages to buster version

pica-db-backup/Dockerfile

@@ -4,8 +4,7 @@ RUN apt-get update && \
     apt-get install -y --no-install-recommends \
     iputils-ping \
     postgresql-client \
-    mysql-client \
-    mongodb-clients \
+    default-mysql-client \
     mongo-tools \
     cron && \
     apt-get clean && \