tests: Investigate failure on latest linuxserver/openssh-server

[daavoo]

Had to pin it in 42cbd91

Example failure: https://github.com/iterative/scmrepo/actions/runs/4172914933/jobs/7224610376#step:6:126

[skshetry]

We can use renovate to update docker-compose files. See https://github.com/iterative/dvc-azure/blob/5ca4807503137b92e54e220087ba3106733e922e/renovate.json for example config.