update nvim

lua/phoenix/plugins/vim-undodir-tree.lua

@@ -0,0 +1,7 @@
+-- this needs to be here because doing it in init.lua is late for this plugin to work
+vim.o.undofile = true
+vim.o.undodir = '/tmp/.phoenix/undo'
+
+return {
+  'pixelastic/vim-undodir-tree',
+}