ST-53 Make project compatible with python 3.5. Add docker requirements.

Signed-off-by: Bruno S. Morgado <jb.morgado@gmail.com>

.gitlab-ci.yml

 # GitLab CI in conjunction with GitLab Runner can use Docker Engine to test and build any application.
 # Docker, when used with GitLab CI, runs each job in a separate and isolated container using the predefined image that is set up in .gitlab-ci.yml.
 # In this case we use the latest python docker image to build and test this project.
-image: python:3.6
+image: python:3.5
 
 # cache is used to specify a list of files and directories which should be cached between jobs. You can only use paths that are within the project workspace.
 # If cache is defined outside the scope of jobs, it means it is set globally and all jobs will use that definition

Pipfile

@@ -20,4 +20,4 @@ sphinxcontrib-websupport = "*"
 [dev-packages]
 
 [requires]
-python_version = "3.6"
+python_version = "3"

docker-requirements.txt

+docutils
+markupsafe
+pygments
+pylint
+pytest
+pytest-cov
+pytest-pylint
+python-dotenv>=0.5.1
+setuptools
+sphinx
+sphinx_rtd_theme
+sphinx-autobuild
+sphinx-rtd-theme
+sphinxcontrib-websupport
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