[Feature] Build hook to be called after cloning

[marcosmoura]

A few plugins that adds completions to a shell have an "install" process.

Example:
https://github.com/g-plane/pnpm-shell-completion
install.zsh generates a completion bin file that will later be used by the pnpm-shell-completion.plugin.zsh plugin file (that can be loaded by Sheldon).

Unless I am missing something, currently there is no way to execute that install.zsh file after cloning the repo.

My request here would be having some sort of hook to be called for build purposes. Something like that:

[plugins.pnpm-completion]
github = "g-plane/pnpm-shell-completion"

[plugins.pnpm-completion.hooks]
build = "install.sh"