CI: Only build Debian packages for the master branch

.gitlab-ci.yml

@@ -18,6 +18,8 @@ build:src:
   artifacts:
     paths:
       - build-deb/
+  only:
+    - master
 
 build:pkg:
   stage: build_pkg
@@ -28,6 +30,8 @@ build:pkg:
   artifacts:
     paths:
       - output-deb/
+  only:
+    - master
 
 upload:pkg:
   stage: upload
@@ -35,4 +39,6 @@ upload:pkg:
   script: "upload-packages"
   dependencies:
     - build:pkg
+  only:
+    - master