gitlab-ci: Drop package pipeline upload jobs for release branch

The package pipeline for release versions should not upload packages
automatically to our archive of nightly development versions.

.gitlab-ci.yml

@@ -52,7 +52,7 @@ prep:doc-package:
         - .cmake_doc_artifacts
         - .run_only_for_package
 
-upload:source-package:
+.upload:source-package:
     extends:
         - .rsync_upload
         - .run_only_for_package
@@ -199,7 +199,7 @@ build:linux-x86_64-package:
     needs:
         - prep:doc-package
 
-upload:linux-x86_64-package:
+.upload:linux-x86_64-package:
     extends:
         - .rsync_upload
         - .run_only_for_package
@@ -223,7 +223,7 @@ build:linux-aarch64-package:
     needs:
         - prep:doc-package
 
-upload:linux-aarch64-package:
+.upload:linux-aarch64-package:
     extends:
         - .rsync_upload
         - .run_only_for_package
@@ -298,7 +298,7 @@ build:macos-package:
     needs:
         - prep:doc-package
 
-upload:macos-package:
+.upload:macos-package:
     extends:
         - .rsync_upload
         - .run_only_for_package
@@ -321,7 +321,7 @@ build:macos10.10-package:
     needs:
         - prep:doc-package
 
-upload:macos10.10-package:
+.upload:macos10.10-package:
     extends:
         - .rsync_upload
         - .run_only_for_package