Bump packages to v0.1.3, update podspecs

Release prep for v0.1.3: update changelogs and bump versions for cnativeapi and nativeapi packages. Update iOS and macOS podspecs to v0.1.3 and remove the duplicate macOS deployment target entry from the macOS podspec. Document example changes: remove CocoaPods from the storage example and switch the Darwin/storage example to Swift Package Manager; update nativeapi's dependency on cnativeapi to ^0.1.3.

chore: bump packages to 0.1.2

Fix publish workflow: single job with submodules and dart-lang steps