[2.x] Upgrade to league/flysystem V2

[erikn69]

Acording to thephpleague Upgrade to 2.x (needs to be improved but it's a good start)
It is passing all tests from league/flysystem-adapter-test-utilities class AdapterTestUtilitiesFilesystemAdapterTestCase:

PHPUnit 9.5.4 by Sebastian Bergmann and contributors.

Runtime:       PHP 8.0.5
Configuration:  \google_flysystem\phpunit.xml.dist

BEGIN: .............................................                    46 / 46 (100%)

Time: 02:23.580, Memory: 10.00 MB

OK (46 tests, 75 assertions)

NOTE: Please also create a new branch 1.x from commit fb7977f Adding functionallity to clear the cache on demand for to maintain support and send corrections to the old version, also don't forget the release for the two versions

[masbug]

Thank you