Fix actions endpoint for block dropdowns

[maths22]

Make it so you can use this library for interactive dropdowns. Those callbacks don't have a response url, so make it optional.

[dangerpr-bot]

	1 Error
:no_entry_sign:	Please put back the * Your contribution here. line into CHANGELOG.md.

	1 Warning
:warning:	There’re library changes, but not tests. That’s OK as long as you’re refactoring existing code.

Generated by :no_entry_sign: danger

[dblock]

Thanks, care to put this in CHANGELOG please, and maybe write a quick test with an actual payload?

[dblock]

Want to finish this @maths22 ?

[maths22]

Whoops, I forgot about this; will add tests

[maths22]

@dblock done and confirmed it passes locally; travis doesn't seem to be running to validate it there

[dblock]

It's cause this:

We'll have to migrate this project to GHA, maybe someone (you?) could take care of it.

[crazyoptimist]

@maths22 now you can merge master into your branch then CI will pass.

[maths22]

Ok it should be ready to run tests once you approve running them

[crazyoptimist]

@dblock danger is failing with this message:

Missing ENV['DATABASE_ADAPTER'].
Could not find the type of CI for Danger to run on.

Have you experienced the same? Please gimme some hints if yes.
I will investigate it and commit on the next PR(mongo v5 one).

[dblock]

@CrazyOptimist I don't quite understand why this happens, but it looks like adding a checkout depth of 0 fixes the problem on other repos? Copy the rest of https://github.com/slack-ruby/slack-ruby-bot-server/blob/master/.github/workflows/danger.yml#L10

[dblock]

I merged this, care to PR an update to that dangerfile @CrazyOptimist and let's see if that happens with the change?

[crazyoptimist]

Roger!