Change: Pass only storageOptions to Storage constructor

[jukkah]

Change Storage constructor to accept only storageOptions passed to Umzug constructor. In addition, try to figure out if created storage doesn't support this and use old format as fallback. Old style will be dropped in some major version in future, probably in version 3. This affetcs to all custom storages.

DEPRECATED

• Storage constructors doesn't accept options that contains storageOptions any more. They accept only storageOptions directly.

- let storage = new Storage(this.options)
+ let storage = new Storage(this.options.storageOptions)

If you are writing a custom Storage and want to support Umzug v1- follow these instructions

constructor(options) {
  // convert options from v1- to v2+
  if (options.storageOptions) {
    options = options.storageOptions
  }

  // continue as normal
  this.option1 = options.option1
}

[mention-bot]

@jukkah, thanks for your PR! By analyzing the history of the files in this pull request, we identified @rpaterson, @sdepold and @Americas to be potential reviewers.