Test against ruby-head

[casperisfine]

      STACK_FRAMES_BUFFER.find do |frame|
        path_match = frame.path.match(path_regexp)
      end

This crash on ruby-head with NoMethodError: undefined method match' for nil:NilClass`.

Trying to see if there's something wrong in this gem or if it's normal.

[casperisfine]

Ok, I think it's simply https://bugs.ruby-lang.org/issues/17018 ruby/ruby#3299

It now return cfunc frame which don't have a .path. Not sure if this gem should filter them or not, but regardless, It's easy to work around.

[dylanahsmith]

This library allows the user of it to specify the size of the buffer to capture the frames, so it seems like a leaky abstraction to try to hide C frames. That could confuse the code using it into behaving as it had captured the entire stack because less frames are exposed than the buffer can capture.

Ideally, we would skip the StackFrames::Buffer#capture method, but I think that is blocked on https://bugs.ruby-lang.org/issues/14607 to do that without the above mentioned leaky abstraction.

I'll open a PR to fix the tests on ruby 3.

[dylanahsmith]

travis-ci.org no longer works, so I'll switch to Github Actions for CI