genappimage.sh uses features that doesn't work with older cmake
versions. Also replace NVIM_BUIL...

It's needed to give the determine the correct neovim version

The PPA for cmake didn't seem to work, so we manually install cmake
instead. Install `cmake` fro...

Sync with neovim workflow.

A newer version of cmake is needed to build neovim.

The `install_deps.sh` script from neovim repo no longer works as the
`--container` option has be...

They're already provided as is by neovim.