[CI] Stop triggering pacxx-docker rebuilds, they'll be done nightly.

See: https://gitlab.dune-project.org/joe/pacxx-docker/issues/27

Copied from
pacxx-llvm2!8

ci-main.yml

@@ -4,15 +4,11 @@
 # The including file should set the variable ADOPT to whereever it's
 # checked-out files should end up in pacxx's source tree, see the --adopt=
 # parameter in base/getpacxx.
-#
-# The project should set the protected CI variable DOCKER_REBUILD_TOKEN to a
-# token that can be used to trigger rebuilds for the docker images
 
 stages:
 - source
 - build
 - test
-- deploy
 
 ######################################################################
 #
@@ -217,22 +213,3 @@ test-cuda-make-release:
   - ctest -j$(nproc) -L '^cuda-release-known-failure$' --output-on-failure || true
   tags:
   - hpc2seci-nvidia
-
-######################################################################
-#
-#  Deploy: Trigger rebuild of the docker images
-#
-
-trigger-docker-rebuild:
-  stage: deploy
-  image: alpine:latest
-  variables:
-    GIT_STRATEGY: none
-  script:
-  - apk add curl
-  - curl -f -X POST -F token=$DOCKER_REBUILD_TOKEN -F ref=master https://gitlab.dune-project.org/api/v4/projects/702/trigger/pipeline
-  tags:
-  - hpc2seci
-  dependencies: []
-  only:
-  - master