fix: bump Elixir LS version

Closes #215

Author: mhanberg

lua/elixir/elixirls/init.lua

@@ -9,7 +9,7 @@ local Utils = require("elixir.utils")
 local capabilities = vim.lsp.protocol.make_client_capabilities()
 capabilities.textDocument.completion.completionItem.snippetSupport = true
 
-local default_install_tag = "tags/v0.19.0"
+local default_install_tag = "tags/v0.22.0"
 
 local elixir_nvim_output_bufnr