Do not enforce no-cache builds on changes do Dockerfiles, Docker takes care of this

.gitlab-ci.yml

@@ -17,7 +17,6 @@ detect_changes:builder:
   stage: .pre
   rules:
     - changes:
-        - containers/builder/Dockerfile
         - containers/builder/spack.yaml
         - spack/packages/**/*
   script:
@@ -27,7 +26,6 @@ detect_changes:release:
   stage: .pre
   rules:
     - changes:
-        - containers/release/Dockerfile.in
         - containers/release/configure_release.sh
   script:
     - mkdir -p .ci-env