Try to fix CI for MR pipelines

.gitlab-ci.yml

@@ -4,8 +4,8 @@ trigger_mr:
     ENVIRONMENT: test
     UPSTREAM_REF: $CI_COMMIT_REF_NAME
     MR_REF: $CI_MERGE_REQUEST_REF_PATH
-  only:
-    - merge_requests
+  rules:
+    - if: $CI_PIPELINE_SOURCE == 'merge_request_event'
   script:
     - 'curl --fail --request POST --form token=$WEB_TRIGGER_TOKEN --form ref=master --form "variables[MR_REF]=$MR_REF" --form "variables[ENVIRONMENT]=test" --form "variables[UPSTREAM_REF]=$CI_COMMIT_REF_NAME" "https://gitlab.nektar.info/api/v4/projects/374/trigger/pipeline"'
 
@@ -13,8 +13,8 @@ trigger_deploy:
   variables:
     ENVIRONMENT: deploy
     UPSTREAM_REF: $CI_COMMIT_REF_NAME
-  only:
-    - master
+  rules:
+    - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH
   trigger:
     project: nektar/nektar-publications-web
     strategy: depend