Fix macos release followup

[juliankuners]

The previous pull request #4852 succesfully fixed an error that made the homebrew build of k not build in CI.

It turns out that there is another unrelated error during testing of that homebrew build, see logs. brew cannot find the local bottle (brew package) when trying to install.

[juliankuners]

In the macos image that is used in the workflows, the brew version has been updated from 4.6.3 to 4.6.6. Though the workflow runs brew update in CI, which makes it unclear which versions were specifically used.

It looks like recent versions of brew disallow installing packages from a local path without throwing a warning or error. There is the environment variable HOMEBREW_FORBID_PACKAGES_FROM_PATHS that is enabled by default, but setting it to any value, including 0 or false, triggers the flag, see here.

There is also the undocumented environment variable HOMEBREW_INTERNAL_ALLOW_PACKAGES_FROM_PATHS that could be set to enable local paths, but the environment variable is unset by brew beforehand. I also tried out the environment variable in CI as well as locally and it didn't work.

Finally, there's the environment variable HOMEBREW_DEVELOPER that can be set, which also enabled local paths. With this, the installation progresses in CI. Though this has the disadvantage that warnings are now treated as errors.

There is now a new issue that I cannot replicate locally on my x86_64 linux machine, see logs. brew cannot find the file /opt/homebrew/Cellar/llvm/17.0.6 after installation of llvm@17. Looking at previous successful CI runs and my local installation with brew install llvm@17 -v, brew instead reads the file /opt/homebrew/Cellar/llvm@17/17.0.6. Somehow @17 disappeared for no good reason.

[juliankuners]

Brew builds are currently not planned to be actively maintained by specifically RV for the foreseeable future.

MacOS builds can also alternatively be installed with kup: https://docs.runtimeverification.com/kontrol/cheatsheets/kup-cheatsheet