Fix sample in Azure function README.md

[donovamb]

The sample was missing a parameter in the calls to the apollo server. I also added a note about a current issue with local development of Azure functions on Macs.

Fixes #684 .

TODO:

• Update CHANGELOG.md with your change (include reference to issue & this PR)
• Make sure all of the significant new logic is covered by tests
• Rebase your changes on master so that they can be merged easily
• Make sure all tests and linter rules pass

[apollo-cla]

@donovamb: Thank you for submitting a pull request! Before we can merge it, you'll need to sign the Meteor Contributor Agreement here: https://contribute.meteor.com/

[abernix]

Merging this in to get the update for the schema in there, which is certainly relevant!

In regard to the macOS Warning: I've gone ahead and removed it right now since the issue you linked to has been closed. If that's still relevant, please open a new PR!

Thanks for opening this PR originally!