Label potential missing changes

It is fairly common that changes in some files imply changes in other files.

As an example, modifying files in the src directory might need changes in the docs directory.

api-version: reviewpad.com/v3.x

labels:
  missing-specs:
    description: Likely missing specs
    # color is the hexadecimal color code for the label, without the leading #.
    color: "294b69"

rules:
  - name: codeChangesImplySpecChanges
    kind: patch
    description: Changes to src and not to spec
    spec: $hasFilePattern("src/**") && !$hasFilePattern("docs/**")

workflows:
  - name: check-for-specs
    description: Check for specs
    if:
      - rule: codeChangesImplySpecChanges
    then:
      - $addLabel("missing-specs")

You can see this policy in the following pull request reviewpad/action-demo/#2.