converted build job to a template job

.gitlab-ci.yml

@@ -1,7 +1,7 @@
 stages:
   - build
 
-build:
+.build:
   image: debian:stable-slim
   stage: build
   before_script:
@@ -10,11 +10,18 @@ build:
   script:
     - cd ~/.fg42/ && fg42 -nw --script build.el
 
+build-branches:
+  extends: .build
+  only:
+    - branches
+  except:
+    - tags
+
 build-package:
-  extends: build
+  extends: .build
   script:
     - cd ~/.fg42/ && fg42 -nw --script build.el
-    - cd && tar zcf fg42.$CI_COMMIT_TAG.tar.gz ~/.fg42/
+    - cd && tar zcf ~/fg42.$CI_COMMIT_TAG.tar.gz ~/.fg42/
   artifacts:
     when: on_success
     paths: