Log Message:
Update to 1.0.3.

Trac 1.0.3 is a maintenance release containing numerous fixes and minor
enhancements. The following are a few of the highlights:

  - Notification is sent when adding an attachment to a ticket (#2259).
  - Stylesheets and scripts are loaded during autopreview, resulting in proper
    syntax highlighting when code WikiProcessors are added (#10470) and display
    of Workflow graphs without explicit autopreview (#10674).
  - Merge changesets are shown as differences against first parent, resulting
    in less noisy changesets (#10740).
  - Pygments 2.0 is supported (#11796).
  - Fixed error when completing the `initenv` TracAdmin command (#11797).
  - Performance improvement on systems with many thousands of authenticated
    users due to caching of Environment.get_known_users (#11868).
  - Distribution metadata of wheel package is supported and displayed on the
    About page (#11877).