Bump ElixirLS default version

[kevinkirkup]

The latest version is failing to install elixir-ls with OTP 26.
Looks like we need to be pointing to elixir-ls:0.15.1

Related issue: elixir-lsp/elixir-ls#886

[ERROR][2023-07-19 14:52:43] .../vim/lsp/rpc.lua:734	"rpc"	"/User/username/.cache/nvim/elixir-tools.nvim/installs/elixir-lsp/elixir-ls/tags_v0.15.0/1.15.2-26/language_server.sh"	"stderr"	"running /Users/kevinkirkup/.cache/nvim/elixir-tools.nvim/installs/elixir-lsp/elixir-ls/tags_v0.15.0/1.15.2-26/launch.sh\nLooking for ASDF install in /Users/kevinkirkup/.asdf/asdf.sh\n"
[ERROR][2023-07-19 14:52:46] .../vim/lsp/rpc.lua:734	"rpc"	"/User/username/.cache/nvim/elixir-tools.nvim/installs/elixir-lsp/elixir-ls/tags_v0.15.0/1.15.2-26/language_server.sh"	"stderr"	"Runtime terminating during boo"
[ERROR][2023-07-19 14:52:46] .../vim/lsp/rpc.lua:734	"rpc"	"/User/username/.cache/nvim/elixir-tools.nvim/installs/elixir-lsp/elixir-ls/tags_v0.15.0/1.15.2-26/language_server.sh"	"stderr"	"t ({badarg,[{io,put_chars,[standard_error,[_]],[{_},{_},{_}]},{Elixir.Kernel.CLI,exec_fun,2"
[ERROR][2023-07-19 14:52:46] .../vim/lsp/rpc.lua:734	"rpc"	"/User/username/.cache/nvim/elixir-tools.nvim/installs/elixir-lsp/elixir-ls/tags_v0.15.0/1.15.2-26/language_server.sh"	"stderr"	",[{_},{_}]},{Elixir.Kernel.CLI,run,1,[{_},{_}"
[ERROR][2023-07-19 14:52:46] .../vim/lsp/rpc.lua:734	"rpc"	"/User/username/.cache/nvim/elixir-tools.nvim/installs/elixir-lsp/elixir-ls/tags_v0.15.0/1.15.2-26/language_server.sh"	"stderr"	"]},{elixir,start_cli,0,[{_},{_}]},{init,start_em,1,[]},{init,do_boot,3,[]}]})\r\n"
[ERROR][2023-07-19 14:52:46] .../vim/lsp/rpc.lua:734	"rpc"	"/User/username/.cache/nvim/elixir-tools.nvim/installs/elixir-lsp/elixir-ls/tags_v0.15.0/1.15.2-26/language_server.sh"	"stderr"	"\r\nCrash dump is being written to: er"
[ERROR][2023-07-19 14:52:46] .../vim/lsp/rpc.lua:734	"rpc"	"/User/username/.cache/nvim/elixir-tools.nvim/installs/elixir-lsp/elixir-ls/tags_v0.15.0/1.15.2-26/language_server.sh"	"stderr"	"l_crash.dump..."

[kevinkirkup]

To resolve, you can specify the explicit tag version in the elixir-ls section of the configuration:

local elixir = require("elixir")
local elixirls = require("elixir.elixirls")

elixir.setup {
  nextls = {...},
  credo = {...},
  elixirls = {
    tag = "v0.15.1", -- defaults to nil, mutually exclusive with the `branch` option
    settings = elixirls.settings {...},
  }
}