Add support for FCM http2 API

[mtrezza]

New Feature / Enhancement Checklist

• I am not disclosing a vulnerability.
• I am not just asking a question.
• I have searched through existing issues.

Current Limitation

#219 added support for the FCM HTTP v1 API, which supports HTTP/2 connectivity.

Feature / Enhancement Description

Add support for sending push notifications via HTTP/2 connectivity when using FCM.

3rd Party References

• https://eladnava.com/send-multicast-notifications-using-node-js-http-2-and-the-fcm-http-v1-api/
• https://www.npmjs.com/package/fcm-v1-http2

[parse-github-assistant]

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[mtrezza]

@jimnor0xF you wrote #219 (comment); could you please elaborate a bit what's to do here, if anything? cc @mman

[jimnor0xF]

@mtrezza
Unfortunately, firebase-admin-node in its current state does not use/support HTTP/2 at the moment.
So we are dependent on the maintainers for that package to add support for that first.

There is a PR up: firebase/firebase-admin-node#2550, so hopefully it is merged soon.
It probably will, since this is a pretty critical oversight on their part considering that the old API is supposed to be removed next month.

[mtrezza]

It seems the required PR has been merged today: firebase/firebase-admin-node#2550

Could we already start to prepare a PR that works with that change?

[jimnor0xF]

@mtrezza
Should be to just bump the version of the package to v12.3.0 from what I understand. Defaults to http2.

[mtrezza]

From firebase/firebase-admin-node#2488 (comment):

This can be enabled by using the enableLegacyTransport() method. This method is already marked as deprecated and will be removed once the HTTP/2 transport is considered fully stable.

Then maybe we should expose this method as well? Or will there be a way for developers access it?

[parseplatformorg]

🎉 This change has been released in version 6.5.0