0.39.0.beta.1

Enhancments

• Gracefully handle missing root podspecs when auto-detecting.
  Hugo Tunius
  #3919
• When comparing versions with unequal numbers of trailing zeros, the one with
  fewer zeros will only compare less than the other when they are otherwise
  equal.
  Gabriele Petronella
  cocoapods.org#185
• Support converting objects of arbitrary classes to YAML.
  Samuel Giddins
  CocoaPods#3907
• Add a 'public_only' flag to linter results for warnings that are only
  appropriate for public specification.
  Samuel Giddins
  #190
  CocoaPods#2682