test: add public-gateway-smoke-test.sh

[lidel]

This PR adds a small test suite for checking if there are any known regressions at the public gateway.

Created to catch regressions such as ipfs-shipyard/ipfs-share-files#17 (comment) and help with future migration to dweb.link.

@lgierth: not sure if this is what you had in mind, but at least it can be used for smoke-testing ipfs-shipyard/ipfs-share-files#17 (ipfs.io vs ipfs.infura.io):

$ bash /public-gateway-smoke-test.sh ipfs.io
==> Running a bunch of HTTP requests to ipfs.io to see if it follows requirements of Public Gateway..
(...)
--> Testing /api/v0/ ..

plain curl GET: OK
local CORS fetch: Error on line 110
FAIL

[eefahy]

Hi @lidel - I like the idea a lot! I'm thinking through how we could run this in an automated way on gateway changes. I'm happy to merge this now and return to it when we have the gateway deploy pulled out onto its own repo and deployments to it happen via CI/CD. Or perhaps we keep it open to remind us it's there? LMK your preference

[lidel]

👍 for plugging those tests into gateway change pipeline.

I think its okay to keep it open until gateway gets its own repo, does not need to be actually merged into ipfs/infra.

[thattommyhall]

I did this in another repo