Improve concat to accept numeric values

[anderseknert]

When trying to build JSON paths from an array of strings and numbers, concat will fail:

r := concat("/", ["path", 0, "foo"])

1 error occurred: policy.rego:5: rego_type_error: concat: invalid argument(s)
	have: (string, array<string, number, string>, ???)
	want: (delimiter: string, collection: any<array[string], set[string]>, output: string)

We can of course work around this by first converting all numbers in the array to strings, but it would be more convenient if concat treated numbers as strings in the first place. I can't think of any reason it shouldn't.

[sunjh]

Please assign to me, I can work on this, thanks!

[sunjh]

Working in progress. Will create pull request after the internal PR review.

[sunjh]

Hi @anderseknert , the change is ready, but when I try to create a PR, it says I must be a collaborator. Do you know what should I do to open this PR?

[anderseknert]

You have to first fork OPA, then submit the PR from your fork

[srenatus]

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/about-forks