Add Calypso status check

[alshakero]

Proposed Changes

This adds a GitHub action that checks the status of Calypso Channel on Slack. It allows us to get rid of this Tampermonkey script and its quirks. Also, not everyone is aware of this script.

Testing Instructions

Blocked by: D156224-code

1. To install GH actions locally, you can use act, it's very straightforward.
2. In Calypso repo's root, install act by running curl --proto '=https' --tlsv1.2 -sSf https://raw.githubusercontent.com/nektos/act/master/install.sh | sudo bash.
3. Run the action by running act -P ubuntu-latest=catthehacker/ubuntu:act-latest merge_group -s CALYPSO_CHANNEL_STATUS_API_SECRET=PING ME FOR THE SECRET.
4. Sadly, you can't test the endpoint unless it's deployed because Docker requires a business account to use SOCKS proxy (i.e access your sandbox).

Next steps

1. Enable merge queue.

[matticbot]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-114896

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-114896&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-114896&env=a8c-for-agencies

[matticbot]

This PR does not affect the size of JS and CSS bundles shipped to the user's browser.

Generated by performance advisor bot at iscalypsofastyet.com.

[matticbot]

This PR modifies the release build for the following Calypso Apps:

For info about this notification, see here: PCYsg-OT6-p2

• notifications
• wpcom-block-editor

To test WordPress.com changes, run install-plugin.sh $pluginSlug add/calypso-status-check on your sandbox.

[tyxla]

Code looks good 👍

I'm happy to try that out, but if we end up using it I'd like us to make sure it's very well documented. There might be a bunch of places that need to be updated - the docs in the repo, the deployment docs in the FG (including the fact that if you're sandboxing the API, the response might be slower, and it might affect your PR merge experience), and there will have to be a PSA written to let all Calypso devs know about the change.

[alshakero]

including the fact that if you're sandboxing the API, the response might be slower

If I understand correctly, GitHub servers will access the endpoint, and they won't go through my sandbox. Is that right?

[tyxla]

including the fact that if you're sandboxing the API, the response might be slower

If I understand correctly, GitHub servers will access the endpoint, and they won't go through my sandbox. Is that right?

That sounds correct, as long as we limit the usage of the endpoint to the GitHub action 👍