Update authors and changelog for v2.8.0.

[seanlip]

Explanation

This PR updates the authors and changelog for the v2.8.0 release.

Checklist

• The PR title starts with "Fix #bugnum: ", followed by a short, clear summary of the changes. (If this PR fixes part of an issue, prefix the title with "Fix part of #bugnum: ...".)
• The PR explanation includes the words "Fixes #bugnum: ..." (or "Fixes part of #bugnum" if the PR only partially fixes an issue).
• The linter/Karma presubmit checks have passed.
  • These should run automatically, but if not, you can manually trigger them locally using python scripts/pre_commit_linter.py and bash scripts/run_frontend_tests.sh.
• The PR is made from a branch that's not called "develop".
• The PR follows the style guide.
• The PR is assigned to an appropriate reviewer.

[DubeySandeep]

LGTM!

[codecov-io]

Codecov Report

Merging #6535 into develop will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop    #6535   +/-   ##
========================================
  Coverage    75.77%   75.77%           
========================================
  Files          992      992           
  Lines        78618    78618           
  Branches      4652     4652           
========================================
  Hits         59574    59574           
  Misses       19044    19044

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update a4cbcd0...fa56cab. Read the comment docs.

[seanlip]

Thanks @DubeySandeep !