Readme links to docs broken

[TylerAHolden]

Issue Summary

all readme links to docs seem to be broken

Steps to Reproduce

1. Click on any of the links that take you to api docs (https://sendgrid.com/docs/API_Reference/api_v3.html)
2. See broken link 404 page

I think the correct link would be https://sendgrid.com/docs/api-reference/ but I'm not actually sure if that's the documentation that was intended to be linked.

[JenniferMah]

Hi @TylerAHolden
Thanks for bringing this to our attention. These links in the readme should link to sendgrid.com/docs/api-reference. If you would like to you can open a PR to change these links in the read.me or I can open a ticket internally to get this change prioritized in our backlog.