feat(gitlab): add ci to automatically update parent project

.gitlab-ci.yml

@@ -0,0 +1,27 @@
+trigger:
+  stage: trigger
+  image: quay.io/curl/curl:latest
+  script:
+    # Put the private-token with a colon into a variable to escape the "Linefeed-Limbo" (https://stackoverflow.com/a/51187502)
+    - PRIVATE_TOKEN="${PRIVATE_TOKEN}:"
+
+    # Get the current datetime (in local time with the TZ variable)
+    - CURRENT_DATE="$(date +'%F %T')"
+
+    # Add it to each commit message of the repository (and make sure there is no carriage returns)
+    - MESSAGE="${COMMIT_MESSAGE:-$CI_COMMIT_MESSAGE} (${CURRENT_DATE})"
+    - MESSAGE=$(echo "${MESSAGE}"|tr -d '\n')
+
+    # Use the Repository submodules API to update the submodule reference in the repository
+    - curl
+      --data "branch=${BRANCH:-$CI_DEFAULT_BRANCH}&commit_sha=${COMMIT_SHA:-$CI_COMMIT_SHA}&commit_message=${MESSAGE}"
+      --header "${PRIVATE_TOKEN} ${GITLAB_TOKEN}"
+      --request PUT
+      "${CI_SERVER_URL}/api/v4/projects/${PROJECT_ID}/repository/submodules/${SUBMODULE_PATH}"
+  rules:
+    - changes:
+        - post/
+  variables:
+    PROJECT_ID: '8'
+    SUBMODULE_PATH: 'content'
+    TZ: ':Europe/Paris