Ensure compatibility with updates of dependencies

[timvink]

Problem Description

probatus has dependencies that are not pinned:

probatus/setup.py

Lines 25 to 34 in 2723c88

	install_requires=[
	"scikit-learn>=0.22.2",
	"pandas>=1.0.0",
	"matplotlib>=3.1.1",
	"scipy>=1.4.0",
	"joblib>=0.13.2",
	"tqdm>=4.41.0",
	"shap>=0.36.0",
	"numpy>=1.19.0"
	],

That is user-friendly, but introduces the risk that updates to downstream dependencies break probatus without us knowning.

Desired Outcome

Notification of breaking updates.

Solution Outline

There are two main methods to deal with this:

1. Run unit tests on a schedule (f.e every couple of days), so you get a broken build you can fix. As an example, see this PR from scikit-lego Schedule dependencies workflow file added koaning/scikit-lego#378
2. Fix dependencies to the latest version, and use dependabot to automatically open an PR (and thus trigger unit tests) when a dependency is updated.

Both options have upsides and downsides. I'm inclined to 'force' users to use the latest versions (option 2), creating a new release for updated dependencies as soon as they pass unit tests.

[Matgrb]

#97 covers the discussion around this topic.

We have decided to not use dependabot, in order to not force the users to use the newest version of all packages.

[timvink]

There is another way however. If we run the unit tests everyday, we will know pretty soon if probatus is breaking when any of the dependencies have updated (because we use >= in dependencies).

Opened #113 to address this.