Makedeb is no longer maintained - consider removing documentation referencing it
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### Problem to solve
http://makedeb.org is no longer available.
The documentation at https://gitlab.com/gitlab-org/cli/-/blob/main/docs/installation_options.md#mpr-debianubuntu can no longer be followed.
As a user who wishes to install `glab`, I want to no longer be shown this invalid information.
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### Proposal
Consider removing references to this site from the documentation.
### Further details
makedeb's maintainer has stepped back from maintaining it: https://hunterwittenborn.com/blog/stepping-back-from-open-source/
See also the git repository at https://github.com/makedeb/makedeb
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### Links / references
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