[!76] [CI] Use ccache only for the pacxx-build step.

Merge branch 'ccache-pacxx-build-only' into 'master'

The other steps use a different compiler anyway.

See merge request [joe/pacxx-docker!76]

  [joe/pacxx-docker!76]: gitlab.dune-project.org/joe/pacxx-docker/merge_requests/76

.gitlab-ci.yml

@@ -283,13 +283,10 @@ stop-mkimage:
   variables:
     GIT_STRATEGY: none
   before_script:
-  - *ccache
   - cat /opt/pacxx/repoversions
   - cat samples/repoversions
   - mkdir bsamples
   - cd bsamples
-  after_script:
-  - *ccache
   tags:
   - hpc2seci
   artifacts:
@@ -336,12 +333,9 @@ samples-build-cuda-make-release:
     GIT_STRATEGY: none
     PACXX_FORCE_DEFAULT_RT: 1
   before_script:
-  - *ccache
   - cat /opt/pacxx/repoversions
   - cat samples/repoversions
   - cd bsamples
-  after_script:
-  - *ccache
 
 test-native-norv-debug:
   <<: *test