Bump pygments dependency to 2.1+

Review Request #8009 — Created Feb. 26, 2016 and submitted — Latest diff uploaded

Information

Review Board
release-2.5.x

Reviewers

Pygments changed their output a little bit which breaks some unit tests in
Djblets. This change updates our dependency to always require the newer style
so we can update those tests.

  • Viewed diffs in the diffviewer and excerpts in HTML emails. Saw no change from
    when running with Pygments 2.0.2.
  • Ran unit tests.