Versioning/tagging of container images

[umarcor]

Currently, images are not versioned explicitly.
Each time a workflow is run, the latest/master/main branch/release of the tools are downloaded and built.
Images are only pushed when builds and tests are successful.

Users which cannot afford breaking changes can use the image by digest, instead of doing it by name.
However, we might improve the usability:

• Images which contain a single tool (such as, yosys, magic, netgen, verilator, gtkwave, ghdl, etc.) might be tagged with the version (git hash) apart from latest.
  • Some months ago, the naming of the images was reworked in order to use / as separators, so that each image/tool has all tags available for itself. That is not possible on docker.io, though; only gcr.io and ghcr.io do support hierarchy in image names.
• With regard to images containing multiple tools, we might use manifests for publishing some versioned ecosystems, implying that we run a full test suite on an specific group of images and we then tag them all together as a nicely behaving family/release.

[umarcor]

Since 781d60c, some images have an explicit version tag, apart from latest. In order to enable it, an stage needs to be added to the Dockerfile and the build stage needs to create /tmp/hdlc.TOOL.version. The file is exported to dist.

See, for example, 2d67113.