Feature: Webhook notifications for Apollo Studio changelog announcement

[setchy]

trafficstars

It would be great to be able to setup notifications (slack and/or webhook) for new Apollo Studio feature announcements as published in CHANGELOG.md. This would allow for engineers to be notified of new feature drops

This would compliment the existing suite of notifications, which includes:

• status page alerts
• schema registry changes
• operation performance alerts (experimental)
• daily summary reports
• build status (preview and webhook-only - see #113 )

[setchy]

As an interim hacky solution we're using the Slack RSS App subscribed to the following CHANGELOG.md atom feed - https://github.com/apollographql/apollo-studio-community/commits/main/CHANGELOG.md.atom

This sends a pretty generic message to our targeted slack channels (guilds, chapters, etc) to let our engineers know there are enhancements in Studio to check out.

This is particularly helpful to drive Studio usage adoption and awareness as we continue our graph journey

[d3rp3tt3]

@zionts, related to our discussions about subscribing to changelogs.