3.20d version support

[abutbul]

I would like to assist with implementing 3.20 docker support.
if anyone started working on this please publish a branch. otherwise I will publish my changes as soon as I start working on it.

[tracker1]

I've not had the time to work on this... the biggest issue has been the migration scripts for moving to the new data configuration format... the use of (sym)links in the container has been problematic, and I haven't had the time to do it.. my own BBS has been effectively offline for a long while... I'll try to find some time in the near future... if you get a PR in for a current version, I'm happy to let it run/update for nightlies.

May just be a matter of pushing a date update... since the time based runners on github stop after a few weeks...

[tracker1]

I've pushed a minor change to the readme which should start nighties (and releases) again... will take a look this weekend.

[abutbul]

i started some new simpler method sent a pull to the vert gitlab.
i will push the branch here as well maybe you can use it (as is or with adaptations)

[abutbul]

#20