Fix garbage component issue of ruby-saml and rexml

[klouvas]

Issue: #201

[adamstegman]

Hi @klouvas, thanks for the contribution! I don't think this requires a fix on our end—applications can update their version of ruby-saml without needing to update this gem.

[klouvas]

@adamstegman It could be resolved by manually bumping the ruby-saml or updating the rexml gem. Wouldn't it be better to upgrade the ruby-xml of the devise_saml_authenticatable to latest stable to resolve all related issue and keep the gem dependencies up to date?

[adamstegman]

If there's a security issue, definitely! But for anything else, it's not our responsibility, and in fact we'd be breaking compatibility with applications using older versions of ruby-saml.