fix: fetchPolicy support for Subscriptions

[MatthieuLemoine]

Hi! 👋

Apollo Client supports fetchPolicy for subscriptions but the fetchPolicy option is not passed to the client in react-apollo.

It can be useful when using no-cache to avoid automatic cache update & handle the update manually using the new onSubscriptionData.

This PR just forwards the fetchPolicy option to apollo-client.

PS: It could be nice to add some kind of note next to a feature in the documentation with the minimum version number needed to use it. Actually, I tried to set fetchPolicy to no-cache because I thought that I could use onSubscriptionData to update the cache but it seems that it was only merged yesterday.

[apollo-cla]

@MatthieuLemoine: 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/

[hwillson]

PS: It could be nice to add some kind of note next to a feature in the documentation with the minimum version number needed to use it. Actually, I tried to set fetchPolicy to no-cache because I thought that I could use onSubscriptionData to update the cache but it seems that it was only merged yesterday.

Yes, I agree this is annoying. This is caused by the fact that our docs are auto published after a docs related PR has been merged. This can happen at any point, and isn't tied to a specific release, which is definitely confusing. Honestly I think the best way to address this (and several other repo workflow issues) is to move away from our current master <-> PR branch workflow, to a master <-> devel <-> PR branch workflow. We could then make sure production docs publishing only happens when devel merges into master, which would only happen when we publish a new release. More on this soon.

[WaldoJeffers]

@hwillson This is a good idea, maybe the issue is less obvious for react-apollo maintainers, but it has happened to me a lot of times (seeing something on the docs, and digging through apollo-client/react-apollo's code only to find out the feature has not been released yet).

[hwillson]

Thanks @MatthieuLemoine!