Remove support of PHP < 8.0

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

:exclamation: No coverage uploaded for pull request base (v5@684410a). Click here to learn what that means.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## v5 #58 +/- ## ===================================== Coverage ? 89.32% Complexity ? 486 ===================================== Files ? 7 Lines ? 1387 Branches ? 0 ===================================== Hits ? 1239 Misses ? 148 Partials ? 0 ```

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[whikloj]

Resolves #56