Dropping support before Node 16.x

Even though the package should work on Node 14. However, the tests are executed on Node 16 and above and hence further modifications in the future may not be compatible with Node 15 or below

• ci: add back lint command before tests 8a294de
• ci: fix tests to run cross platform path assertions 90c3898
• ci: update node versions for running tests 5458ed3
• ci: do not lint before running tests a1e66ca
• refactor: reorganize meta config 03e4823

Full Changelog: v3.3.1...v4.0.0