Remove .tekton/* from CI skip rule

The current CI skip rule prevents testing when only .tekton/* files
change. However, .tekton files contain critical build configuration:
- Pipeline versions (tekton-bundle digests)
- Base image references (REPOS_IMAGE)

Renovate MRs that update these values (!572, !573, !578, !579, !580,
!581) are currently blocked because CI is skipped, creating a catch-22
where dependency updates cannot be validated before merge.

Removing .tekton/* from the skip list allows these updates to be
properly tested while still skipping CI for documentation-only changes.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.gitlab-ci.yml

@@ -11,7 +11,6 @@ workflow:
         - renovate.json
         - README.md
         - LICENSE
-        - .tekton/*
       when: never
     - when: always