Add CI to validate extensions.json

[jtbandes]

Changelog

None

Docs

None

Description

Adds validation script to avoid future errors in extensions.json:

• Check SHA matches
• Check that some required files are present
• Check that readme & changelog point at markdown (text) files rather than HTML or something else
• Warn if files in the .foxe are not compressed (Enable compression for packaged zip (.foxe) files create-foxglove-extension#147)

Checking the id values requires some more attention (and maybe changes to the app) so not solving that in this PR.

Example output:

[linear]

FG-8096 Add validation for extension registry json

[indirectlylit]

We could/should also enforce changelog and readme content in the form of https://raw.githubusercontent.com/.... Most are like this, but some use https://github.com/ domains.

related:

• https://github.com/foxglove/app/pull/6747
• fix URLs for two extensions #35

[bryfox]

🎉 Couple of nitpicks, but this looks great.

I worry slightly that some extensions will never get updated with compression, that we'll get "warning fatigue" when reviewing, and that we'll miss new warnings. The only idea I can think of is to enumerate extensions already in the registry, and elevate that warning to an error if the extension isn't in that set.

[jtbandes]

The only idea I can think of is to enumerate extensions already in the registry, and elevate that warning to an error if the extension isn't in that set.

Sounds good - I can also key this on the SHA to ensure we use compression for future updates to existing extensions