github go library needs updating to support new custom_properties type

[carcunha]

I created a custom property at my organization and set it on a few repos, and then started seeing this on digger workflows:

level=ERROR msg="Failed to parse GitHub context. error parsing GitHub context JSON: json: cannot unmarshal array into Go struct field Repository.repository.custom_properties of type string"

I chatted with cursor, and got this reasoning:

The issue is in the UnmarshalJSON method in models.go. When parsing GitHub events (lines 60-83), it unmarshals into github.PullRequestEvent, github.IssueCommentEvent, etc. from github.com/google/go-github/v55/github. These event types include a Repository struct from the go-github library, which defines custom_properties as a string, but GitHub now returns it as an array.

I see that go-github is currently at v80, and v55 is from september 2023, so this probably needs updating.