v2.0.4 Fix relative paths handling for `load` methods

Thanks to @iiroj for highlighting a bug in okonet/lint-staged/issues/1034 where relative paths did not work appropriately when passed to load methods. This bug has been fixed and tested to make sure this would not happen again 🙂

There were also a few minor improvements:

• Dev dependencies update
• Include nodejs v14 and v16 into PR checks
• Add missing .yml key in add loaded example in readme