Merge branch 'gitlab-ci' into 'master'

Build docs on each commit

See merge request Librem5/developer.puri.sm!20

.gitlab-ci.yml

+job:
+  before_script:
+    - apt-get -y update
+    - apt-get -y install make python3-sphinx
+  tags:
+    - librem5
+  script:
+    - make html
+