Session storage support

[opiation]

While this package is called fp-ts-local-storage, it seems perhaps low-hanging fruit to support sessionStorage as well since it shares the same API. Should you decide to support sessionStorage, an adaption of something similar I've done in my own work might look like...

function setup(storage: Storage) {
  return {
    clear(): void {
      return storage.clear()
    },

    getItem(key: string): IO<Option<string>> {
      return () => fromNullable(storage.getItem(key))
    },

    key(index: number): IO<Option<string>> {
      return () => fromNullable(storage.key(index))
    },

    length(): number {
      return storage.length
    },

    removeItem(key: string): IO<void> {
      return () => storage.removeItem(key)
    },

    setItem(key: string, value: string): IO<void> {
      return () => storage.setItem(key, value)
   }
}

and used as...

// storage.ts
import { setup } from 'insert-lib-name-here'

export const LocalStorage = setup(localStorage)
export const SessionStorage = setup(sessionStorage)

SessionStorage.getItem // ...

Again, I don't know whether sessionStorage is in the roadmap for this lib or if it was intentionally omitted, nor is the above a PR. Just sharing an idea in the event it hasn't been considered yet. Happy to submit a PR if this is deemed worthwhile.

Cheers!