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: 294b69

rules:
  - name: code-changes-imply-spec-changes
    spec: $changed("src/@1.java", "spec/@1.java") == false

workflows:
  - name: check-for-specs
    if:
      - rule: code-changes-imply-spec-changes
    then:
      - $addLabel("missing-specs")