setup-knative fails with jq error

[jku]

sigstore/scaffolding regularly sees an error during setup-knative (example: https://github.com/sigstore/scaffolding/actions/runs/19531750916/job/55916144457#step:9:243):

Run chainguard-dev/actions/setup-knative@b479012116eacde7f895586c17b598f7ba0ee700
...
jq: error (at <stdin>:1): Cannot index string with string "ref"
error: no objects passed to apply
Error: Process completed with exit code 1.

It seems the jq call in question is

curl -L -s https://api.github.com/repos/knative/${REPO}/git/refs/tags | jq -r '.[].ref'

my assumption is that we hit a github rate limit:

• curl does not fail on http errors by default so we don't notice the 403, We just get an error message instead of the expected response
• curl in question happens 8 times during the action
• the unauthenticated rate limit is 60/hour, so in effect the action has a rate limit of 7/hour

I suppose there's multiple possible improvements:

• maybe there is a way to avoid github API altogether -- I made a tentative PR: setup-knative: Avoid GitHub API when possible #656
• at the very least the duplicate curl calls could be refactored out -- this would halve the number of requests
• there could be a better error message so I wouldn't have to guess if we are hitting an API rate limit
• I don't want to provide a GH token to the action but I suppose that would solve the issue as well