feat(src): fix fs promise on different node version

[zhijs]

hi~, i am using this package on my project, and i got this error 'Cannot find module 'fs/promises'', my node version is v12.20.1, so it's better that this package can be use on different node version, that's why i pull this request. fs promise api detail can be found in Update fs.md

[aheissenberger]

Thank you for the link with Table showing the supported syntax.
New Version 1.1.1 is using the old import and should now also work for node >=10.1.0