mambaforge is deprecated since miniforge3 now includes mamba by default

Update CI to use new components [conda]

See merge request docker/base!36

closes #19

Use mambaforge instead of miniconda

See merge request docker/base!7

there are no packages currently in this channel and it seems that it has
been causing build errors recently so remove the channel.

[ci skip]

Use debian base for miniconda image

See merge request docker/base!2

Added conda build

See merge request docker/base!1

can reenable the `lalsuite-dev` trigger once that container has a `conda` branch

just add channels, don't do anything else

and use alpine, its smaller

to enable usage of metapackages down the road

use digest of previous version to stick with SL 7.6