Bump podspec version for AsyncDisplayKit 1.2.3

Merge pull request facebookarchive#538 from facebook/PodspecUpdate122

Update podspec to 1.2.2

Merge pull request facebookarchive#483 from facebook/podfileUpdates

Update .podspec to refer to 1.2.1 release tag.

Merge pull request facebookarchive#461 from facebook/memoryMethods

Updating API names for network range and memory culling before ASDK 1.2 tag.

1.1.1.

1.1.

1.1 beta(tm).

1.0.1.

1.0.

Beta 2.