Make updateQuery option of subscribeToMore optional

[cesarsolorzano]

This patch fix #871 using the recommendations of #879

TODO:

• 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
• Update CHANGELOG.md with your change
• If this was a change that affects the external API, update the docs and post a link to the PR in the discussion

[stubailo]

This looks great, just needs a changelog update, and a PR to the docs mentioning that it's optional!

[helfer]

Thanks a lot @cesarsolorzano! Can you do a quick check to see if we also need a PR to the docs?