OpenTF support

[bpg]

From a technical perspective, I expect that it will be a no-op for the time being as OpenTF anticipates maintaining compat/interop for the foreseeable future.

However, When there is a first official OpenTF release we should be able to:

• add a CI target to run tests against both HC and OpenTF binaries
• add publishing to OpenTF registry
• anything else?

[rafsaf]

This FAQ is indeed good news for now, but maybe another point after yet more time would be abandon HashiCorp's registry at all, but of course with no rush about it (ideally after living in dual registry world for a while when most of users would theoretically use new FOSS registry).

For now imo this is completely ok to use it, but they well... proved to be rather... unstable in keeping their own statues :), so this would be kinda not very surprising for me to see above 9. in FAQ evaporated in incoming months or something after they change their mind, because afaik BSL allows to "force" derived software to change their license model(?).

[bpg]

• Provider: proxmox opentofu/registry#121
• Provider Key: proxmox opentofu/registry#122

[bpg]

Remaining action items:

• add opentofu to the matrix build / test
• update README.md
• anything else?

[bpg]

No more work planned / needed on this, closing