allow CI nightly to fail so badge is green

[Moelf]

There are two ways of doing this, another possibility is to have a separate ci_nightly.yml, let me know if maintainers prefer that route.

[timholy]

The issue is that this failure is going to be on all Julia versions starting with 1.10, so making an exception for nightly soon won't help anything. We just have to fix the test failures.

[Moelf]

but this would be useful for future future? I think it's a general idea to not show red CI badge for Nightly

[timholy]

Fair enough!

[timholy]

Hmm, the badge is still red even though only nightly is failing.

[Moelf]

I wonder if this is correct https://github.com/timholy/Revise.jl/blob/9f7bd4ea3d7b2c3bd37e64130abb718aba2a8072/README.md?plain=1#L3C49-L3C49

[timholy]

If I try updating it with

[![CI](https://github.com/timholy/Revise.jl/actions/workflows/ci.yml/badge.svg)](https://github.com/timholy/Revise.jl/actions/workflows/ci.yml)

(the text supplied by the "Create Status Badge" option, it still shows red.

[Moelf]

ah, we need this line https://github.com/JuliaHEP/UnROOT.jl/blob/77b75d8f8a7d5a6a2b8c408efbcac2c00817e798/.github/workflows/ci.yml#L14C1-L14C51

the allow_failure: true is not a real option, continue-on-error is, but we want to control which step is continue-on-error.

I don't know if we can just replace allow_failure with continue-on-error