Add unit-tests that will found problems with new code

[MaxymVlasov]

What problem are you facing?

New PR's time to time break existing functional, and that can't be found by PR review.
Here one of the examples why we should test corner cases on PR's: #302

Try to use https://github.com/bach-sh/bach Reason: #252 (comment)
Or https://github.com/bats-core/bats-core

[MaxymVlasov]

Tried bach - no idea how to test $ARGS value after common::parse_cmdline execution. Test just not go inside for-loop

Branch: https://github.com/antonbabenko/pre-commit-terraform/compare/chore/GH-303/add_unit_tests-BACH
Commit: 5e563be