Pinning the version of dependencies

[onlinejudge95]

As of now we are not pinning the dependencies version in requirements.txt. A better option in regards to deterministic builds is to use Pipenv for the same. Any opinions on this?

[cclauss]

Nope. We are not shipping a package or application here so repeatable builds are not a goal for this repo. Instead our goal is to spot (via Travis CI and GitHub Action tests) as quickly as possible when any of our algorithms are broken by changes in their dependencies. We chose to allow our dependencies to float so that users of these algorithms have some assurance that they work with current versions of the dependencies that they are built upon.