refactor!: deprecate util.root_pattern

This will be breaking primarily for language servers that rely on
code dependencies that is archived but still needs to be read. More
context: neovim#1687.

Work on neovim#2079.

lua/lspconfig/configs/sourcery.lua

@@ -38,8 +38,7 @@ return {
       token = nil,
     },
     root_dir = function(fname)
-      return util.root_pattern(unpack(root_files))(fname)
-        or vim.fs.dirname(vim.fs.find('.git', { path = fname, upward = true })[1])
+      return vim.fs.dirname(vim.fs.find({'.git', unpack(root_files)}, { path = fname, upward = true })[1])
     end,
     single_file_support = true,
   },