Add support for passing a custom http agent

[ryanolson-aumni]

There are times that you'd need to have a custom http agent for making the authentication requests (via openid-client). This can allow a user to provide their own agent so that they can proxy or do other things that they'd like to do.

• All new/changed/fixed functionality is covered by tests (or N/A)
• I have added documentation for all new/changed functionality (or N/A)

📋 Changes

• Add a configuration option for httpAgent so that users can provide their own http agent for authentication requests (such as an HttpsProxyAgent). This is important for corporate users that require going through a corporate proxy.

[vercel]

@ryanolson-aumni is attempting to deploy a commit to the Auth0 Team on Vercel.

A member of the Team first needs to authorize it.

[ryanolson-aumni]

@adamjmcgrath is this more in line with what you were thinking?

[evansims]

@ryanolson-aumni 👋 Adam is on holiday this week, but he'll get back to you when he returns

[adamjmcgrath]

@adamjmcgrath is this more in line with what you were thinking?

These lgtm - thanks @ryanolson-aumni

You just need to add httpAgent to https://github.com/auth0/nextjs-auth0/blob/main/src/auth0-session/get-config.ts#L114 (use Joi.object().optional())

Also, could you add a note to the docstrings explaining that this option is for the Node runtime only.

[ryanolson-aumni]

Thanks @adamjmcgrath. I added commits that address your feedback. 😀

[adamjmcgrath]

Thanks @ryanolson-aumni!