Add missing fields to Timeline

[devfd]

No description provided.

[google-cla]

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[devfd]

@googlebot I signed it!

[gmlewis]

Thank you, @devfd .
Please make sure to run go generate ./... and push (not force-push) the changes to the PR.
See CONTRIBUTING.md for more details.

[devfd]

my bad, thanks @gmlewis

[codecov]

Codecov Report

Merging #2197 (6089613) into master (0511421) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2197   +/-   ##
=======================================
  Coverage   97.79%   97.79%           
=======================================
  Files         112      112           
  Lines       10003    10003           
=======================================
  Hits         9782     9782           
  Misses        154      154           
  Partials       67       67           

Impacted Files	Coverage Δ
github/issues_timeline.go	100.00% <ø> (ø)

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[gmlewis]

Thank you, @devfd !
LGTM.
Merging.