feat(nvim): use vimux when running tests

roles/neovim/files/after/plugin/vim-test.lua

@@ -12,4 +12,4 @@ map("n", "t<C-s>", ":TestSuite<CR>", options)
 
 vim.g["test#echo_command"] = 0
 vim.g["test#neovim#start_normal"] = 1
-vim.g["test#strategy"] = "neovim"
+vim.g["test#strategy"] = "vimux"

roles/neovim/files/lua/opdavies/plugins.lua

@@ -16,6 +16,9 @@ return packer.startup(function()
 
   use "wbthomason/packer.nvim"
 
+  -- Tmux
+  use "preservim/vimux"
+
   -- Utilities
   use "andymass/vim-matchup"
   use "cakebaker/scss-syntax.vim"