v1.2.13 - Bug fix Release

Fix

• Fix #45: Change the signature of the :func:~deprecated.sphinx.deprecated decorator to reflect
  the valid use cases.

• Fix #48: Fix versionadded and versionchanged decorators: do not return a decorator factory,
  but a Wrapt adapter.

Other

• Fix configuration for AppVeyor: simplify the test scripts and set the version format to match the current version.

• Change configuration for Tox:

  • change the requirements for pip to "pip >= 9.0.3, < 21" (Python 2.7, 3.4 and 3.5).
  • install typing when building on Python 3.4 (required by Pytest->Attrs).
  • run unit tests on Wrapt 1.13 (release candidate).

• Migrating project to travis-ci.com <https://travis-ci.com/github/tantale/deprecated>_.