further cleaning gitlab-ci script

.gitlab-ci.yml

 #image: registry.esss.lu.se/ics-docker/miniconda
 image: python:3.7-slim
 .pip_install_default: &pip_install_default
+    - apt update
+    - apt install git -y
     - pip install scipy matplotlib h5py webdavclient3
 .pip_install_sphinx: &pip_install_sphinx
     - pip install sphinx sphinxcontrib-confluencebuilder sphinxcontrib-blockdiag blockdiag sphinxcontrib-restbuilder sphinx_rtd_theme numpy m2r2
@@ -27,10 +29,10 @@ examples:
 
 pages:
   stage: deploy
-  script:
-    - apt update
-    - apt install git -y
+  before_script:
+    - *pip_install_default
     - *pip_install_sphinx
+  script:
     - python setup.py install
     - sphinx-build -b html -d public/doctrees   doc public
   artifacts:
@@ -41,10 +43,10 @@ pages:
 
 confluence-doc:
   stage: deploy
-  script:
-    - apt update
-    - apt install git -y
+  before_script:
+    - *pip_install_default
     - *pip_install_sphinx
+  script:
     - python setup.py install
     - sphinx-build -M confluence "doc" "doc"
   only: