The elixir-ls team have said that for sourceror to be used in elixir-ls they "need it vendored like dialyxir and jason".
When I checked, this means that the elixir-ls uses a dep branch that has all Dialyxir modules renamed to DialyxirVendored.
Would you consider creating a fork of sourceror e.g. elixir-lsp/sourceror that mirrors the latest sourceror release with all Sourceror modules renamed to VendoredSourceror?