CICD: Fix the travis deployment

[KikeM]

Hi!

The build is reported as failing, but when I have checked the Travis pipeline one can see that it works correctly until the end.

The reason to report as broken is this line in your deployment script defined in .travis.yml:

sh -e /etc/init.d/xvfb start

What is the need behind this line?

Cheers

[dilawar]

• Fixed Travis and also bumped the version after removing deprecation warnings.
• Formatted source code using black.

The CI issue summarised well here https://benlimmer.com/2019/01/14/travis-ci-xvfb/ and official instructions are here https://docs.travis-ci.com/user/gui-and-headless-browsers/#using-xvfb-to-run-tests-that-require-a-gui .

Unfortunately, I could fix is satisfactory. So instead --plot showing up the plot, it takes an additional filename and saves the plot to this file.

[KikeM]

Great, I am glad your pipeline is up again ;)

[dilawar]

Thanks for reporting. The Travis CI was broken for a year after they made changes to their YAML parser.