Untracked files in repos break plugin updates

[EdgeJ]

Problem

If a plugin has untracked or otherwise changed files in the local repository, it cannot be updated.

For example:

- Finishing ... Done!
x lsp_signature.nvim:
    error: The following untracked working tree files would be overwritten by merge:
    	doc/tags
    Please move or remove them before you merge.
    Aborting
    Updating a793d02..62cadce

Proposal

Run git clean and git reset --hard commands under the hood to remove any unexpected local changes when performing updates.