use mongosh to support mongodb 6.x.x

[bessw]

Meteor has been updated to mongodb version 6.0.3, the old mongo shell is not available any more in this version.

Please update mup to support deploying mongodb version 6.0.3 by using mongosh.

When running mup setup it fails with

Running mongo:6.0.3
        2748fee621aea0f3712fa773271e4256f4a886cb4aec68c0152635c0f3879ba9
        Creating replica set
        OCI runtime exec failed: exec failed: container_linux.go:367: starting container process caused: exec: "mongo": executable file not found in $PATH: unknown

Possibly related to: https://github.com/zodern/meteor-up/blob/2272e108dc2c1b227398b175e81dc4b8772e1745/src/plugins/mongo/assets/templates/start.sh#L46

Mup version (mup --version): 1.5.10