Release 0.1.2 for all clients

[mhsdef]

What

Releases version 0.1.2 of all three clients (googly_cloud_storage, googly_cloud_vision, googly_document_ai):

• Version bumps 0.1.1 → 0.1.2 via mix googly.release (mix.exs + README install snippets).
• 0.1.2 changelog entries written, covering the changes since the 0.1.1 release:
  • Read upload File.Stream data as raw bytes so Content-Length matches the body (Read upload File.Streams as raw bytes so content-length matches the body #8)
  • Sanitize Google descriptions so ExDoc docs build clean (Sanitize Google descriptions so ExDoc docs build clean #7)
  • README usage examples call real function heads (Make README usage examples call real function heads #9)

Publishing

After merge, publish each package manually (Hex prompts for passphrase/2FA):

cd clients/googly_cloud_storage && mix hex.publish
cd clients/googly_cloud_vision && mix hex.publish
cd clients/googly_document_ai && mix hex.publish