Export fs/promises function for esm like you do for cjs

[FreePhoenix888]

• Operating System:
• Ubuntu 22.04
• Node.js version:
• Node.js v18.14.0
• fs-extra version:
• fs-extra@11.1.1

Export fs/promises function for esm like you do for cjs

[RyanZim]

In CJS mode, we're exporting wrapped versions of graceful-fs which support either callbacks or promises. We can't do this in ESM, since exports are static. See #746 for detailed discussion.

We could export * from 'fs/promises', but that wouldn't cover native sync methods, which would be confusing, because you'd have to import native sync methods from fs, but fs-extra/esm exports both sync and async methods. Also, this would be inconsistent with the CJS version, since the CJS version exports graceful-fs, not fs.