Make and push only on master

.gitlab-ci.yml

@@ -10,9 +10,10 @@ beamer-build:
   artifacts:
     paths:
       - "*.pdf"
-    expire_in: 5 years
   tags:
     - docker
+  only:
+    - master
 
 synchronize:
   stage: deploy
@@ -29,4 +30,6 @@ synchronize:
   dependencies:
     - beamer-build
   tags:
-    - linux
\ No newline at end of file
+    - linux
+  only:
+    - master
\ No newline at end of file