remove some more unneeded config

.gitlab-ci.yml

@@ -4,20 +4,13 @@ variables:
   LC_ALL: C.UTF-8
 
 before_script:
-  - sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E084DAB9
-  - echo "deb https://cran.rstudio.com/bin/linux/ubuntu trusty/" | sudo tee -a /etc/apt/sources.list
-  - sudo apt-get update -y
-  - rvm default
   - gem install json kramdown jekyll
-install:
   - pip install pyyaml
-script:
-  - make --always-make site
 
 pages:
   stage: deploy
   script:
-    - make serve
+    - make --always-make site
   artifacts:
     paths:
     - public