Auth0 Bug Fix - SAML Issuer

[Matthew Choi]

When using Auth0 SAML issuer url formatted in the following way:

https://dev-abcdef12345.us.auth0.com/samlp/12384569fjkdjfenj123

The saml2aws CLI does not properly parse the URL and returns the following:

Error authenticating to IdP.: error failed to build authentication info: error extractClientInfo: error invalid Auth0 URL      

This originates from this line of code. I believe it needs to be updated to properly parse URLs that include .us like follows:

authURLPattern        = regexp.MustCompile(`https://([^.]+[^.]+)(?:\.us|)\.auth0\.com/samlp/(.+)`)

This way it can match SAML issuer URLs that contain .us, but also still support URLs that do not.

[Mark Gerard]

Can you submit a PR with tests to fix this? @mattchoi2

[vk021013]

+1