Advanced filters

Lovely tool!

One thing that would be nice is to be able to specify additional filter conditions to omit actions/comments under certain conditions.

E.g. (syntax is just a sample)

```yaml
issues:
actions:
enhancement:

# Only comment with a funding request if it the funded label has not yet been set
if: !funded

comment: >
This has been accepted as an enhancement request. Good job :+1:
[Learn how to make it happen](https://make.it.happen/fundmenow).
```

Start by reviewing the action's existing YAML configuration and how labeled issues, pull requests, or discussions trigger comments and other actions. Define the supported condition syntax and its behavior, including the sample check for an absent funded label. Done means conditional filters are documented, consistently applied to the requested actions, and covered by tests.

Written by the indexing model from the issue text.