Address DeprecationWarning for collections.abc

This release fixes code that uses the collections module in Python 3, which raises a DeprecationWarning.

Special thanks for @sloria for the PR.

• Fixed more warnings about importing from collections on Python 3 (thanks to sloria)
  #222

Remove dependency maximum version constraints

This release is compatible with PyYAML v4.2 betas, so users can use a version of PyYAML that does not have the CVE-2017-18342 vulnerability.

Furthermore, this release removes the maximums from dependency version constraints, in order to reduce the maintenance burden. It also has a few bugfixes, increases test coverage, and fixes a warning condition with Python 3.

• Allow space in mimetype before parameters (thanks to miki725)
  #206
• Open up dependency requirements (thanks to blueyed, javabrett)
  #207
  #211
• Increased test coverage with additional vectors, rearranged
  #214
  #216
• Fixed warning about importing from collections on Python 3 (thanks to sloria)
  #215

5.7.0 Release

v5.7.0

5.7.0 Release

5.6.0 Release

v5.6.0

5.6.0 release

5.5.0 Release

v5.5.0

5.5.0 Release

5.4.1 Release

v5.4.1

5.4.1. release

5.4.0 Release

5.4.0 Release

5.2.1 Release

v5.2.1

5.2.1 release

5.2.0 Release

fix release script to not include bdist since bdist_wheel is present

5.1.0 Release

Fix validation of contact field to be of type object