ci: fix docker build job rules by including main branch

.gitlab-ci.yml

@@ -166,7 +166,7 @@ docker:
   variables:
     PARENT_PIPELINE_ID: $CI_PIPELINE_ID
   rules:
-    - if: ($CI_COMMIT_BRANCH == "alpha" || $CI_COMMIT_BRANCH == "alpha" || $CI_COMMIT_BRANCH == "beta") && $CI_PROJECT_NAMESPACE == "adaures"
+    - if: ($CI_COMMIT_BRANCH == "main" || $CI_COMMIT_BRANCH == "alpha" || $CI_COMMIT_BRANCH == "beta") && $CI_PROJECT_NAMESPACE == "adaures"
       exists:
         - CP_VERSION.env
     - if: ($CI_COMMIT_BRANCH == "develop" && $CI_PROJECT_NAMESPACE == "adaures")